23 And not only they, but ourselves also, which have the firstfruits of the Spirit, even we ourselves groan within ourselves, waiting for the adoption, to wit, the redemption of our body.
[AD 253] Origen of Alexandria on Romans 8:23
Even though because of the fact that we believe in Christ our salvation is assured, nevertheless it still remains something to be hoped for; it has not yet been realized.There are different ways of interpreting “the first fruits of the Spirit.” Just as the first fruits of the threshing floor and the wine press are of the same substance as what follows, is it not also true that the Holy Spirit is the first and best of a multitude of other spirits? So to have the first fruits of the Spirit means to have the Holy Spirit, as opposed to a host of other ministering spirits.
The first fruits may also refer to the many gifts of the Spirit. … We apostles, says Paul, have the first fruits of the Spirit, because we were chosen to groan in travail as the Spirit himself does. There is no creature so free of sorrows and sighings that we, who have received the highest and choicest gifts of the Spirit, are not obliged to grieve and sigh over, awaiting the adoption of sons, that is, the perfection of those whom we have been sent to teach and instruct until we see them making enough progress that they deserve to be adopted as sons.
A third possibility is that the first fruits of the Spirit refers to Christ himself, since he is the first born of every creature.

[AD 384] Ambrosiaster on Romans 8:23
For Christians, this world is like the ocean. For just as the sea is whipped up by adverse winds and produces storms for sailors, so also this world, moved by the scheming of wicked men, disturbs the minds of believers. And the enemy does this in so many different ways that it is hard to know what to avoid first, for sources of tribulation are by no means wanting.

[AD 397] Ambrose of Milan on Romans 8:23
The adoption as sons is the redemption of the whole body.

[AD 407] John Chrysostom on Romans 8:23
That is, having had a taste of the things to come. For even if any should be quite stone hard, he means what has been given already is enough to raise him up, and draw him off from things present, and to wing him after things to come in two ways, both by the greatness of the things that are given, and by the fact that, great and numerous as they are, they are but first-fruits. For if the first-fruits be so great that we are thereby freed even from our sins, and attain to righteousness and sanctification, and that those of that time both drove out devils, and raised the dead by their shadow [Acts 5:15], or garments [Acts 19:12], consider how great the whole must be. And if the creation, devoid as it is of mind and reason, and though in ignorance of these things, yet groans, much more should we. Next, that he may give the heretics no handle, or seem to be disparaging our present world, we groan, he says, not as finding fault with the present system, but through a desire of those greater things. And this he shows in the words, "Waiting for the adoption." What do you say, let me hear? You insisted on it at every turn, and cried aloud, that we were already made sons, and now do you place this good thing among hopes, writing that we must needs wait for it? Now it is to set this right by the sequel that he says, "to wit, the redemption of our body." That is, the perfect glory. Our lot indeed is at present uncertainty to our last breath, since many of us that were sons have become dogs and prisoners. But if we decease with a good hope, then is the gift unmovable, and clearer, and greater, having no longer any change to fear from death and sin. Then therefore will the grace be secure, when our body shall be freed from death and its countless ailments (or passions). For this is full redemption (ἀ πολύτρωσις), not a redemption only, but such, that we shall never again return to our former captivity. For that you may not be perplexed at hearing so much of glory without getting any distinct knowledge of it, he partially exposes to your view the things to come, setting before you the change of your body (Gr. changing your body), and along with it the change of the whole creation. And this he has put in a clearer light in another passage, where he says, "Who shall change our vile body, that it may be fashioned like His glorious Body." [Philippians 3:21] And in another place again he writes and says, "But when this mortal shall have put on immortality, then shall be brought to pass the saying that is written, Death is swallowed up in victory." [1 Corinthians 15:54] But to show, that with the corruption of the body the constitution of the things of this life will also come to an end, he wrote again elsewhere, "For the fashion of this world passes away." [1 Corinthians 7:31]

[AD 407] John Chrysostom on Romans 8:23
If the first fruits are enough to free us from our sins and give us righteousness and sanctification … consider how wonderful the whole inheritance must be. If the creation, devoid as it is of a mind and reason and therefore ignorant of these things, nevertheless groans, much more should we groan as well. Next, so as not to give any comfort to the heretics, he says that we do not groan because of the inadequacies of the present system but because we desire something which is much better.

[AD 418] Pelagius on Romans 8:23
Not only do the angels, who are kinder than we are, grieve over these unrepentant people, but we who have the Holy Spirit groan for such people.

[AD 430] Augustine of Hippo on Romans 8:23
Paul now speaks about those of us who already believe. For although we serve the law of God with our spirit (i.e., our mind), our flesh still serves the law of sin for as long as we suffer mortal pains and anxieties.… Adoption is already guaranteed for those who believe, but it has been accomplished only spiritually, not physically. The body has not yet received its heavenly transformation, although the spirit, which has turned from its errors to God, has already been changed through the reconciliation of faith. Therefore even believers still await the revelation which will come in the resurrection of the body. This is the fourth state, when everything will be in perfect peace at eternal rest, completely free of malignant corruption or nagging torment.

[AD 444] Cyril of Alexandria on Romans 8:23
The corruptible body weighs down the soul, and the earthly body pulls down a mind full of cares. For as soon as the Spirit comes to dwell in us and turns us to the study of virtue, the love of the flesh jumps up to combat it, and the law in our members, which is prone to silly lusts, begins a bitter struggle. That is why we groan waiting for the liberation of our bodies as a result of the adoption.

[AD 1274] Thomas Aquinas on Romans 8:23
After showing the excellence of future glory from the longing of the creature [n. 656], the Apostle now shows the same from the longing of the apostles. For that cannot be a trifle which is desired so anxiously by great men. In regard to this he does two things: 332 first, he states his proposition; secondly, he proves it [v. 24; n. 681]. 676. In regard to the first he does three things [n. 679, 680]. First, he describes the dignity of those longing when he says: And not only the creature awaits the glory of the sons of God, but we ourselves, namely, the apostles, who have the first fruits of the spirit, namely, because the apostles had the Holy Spirit before others and more abundantly than others, just as earthly fruit which ripens earlier is richer and more delicious: "Israel was holy to the Lord, the first fruits of his harvest" (Jer 2:3); "You have come to the assembly of the first-born who are enrolled in heaven" (Heb 12:23). From this it is clear that the apostles are greater than all other saints no matter what their credentials, whether virginity or learning or martyrdom, because they have the Holy Spirit more fully. 677. But someone might say that some other saints have endured more torture and greater austerities for Christ than the apostles. But it should be recognized that the amount of one’s merit depends principally and in respect to essential reward on charity. For the essential reward consists in the joy one has in God. But it is plain that one who loves God more will enjoy Him more. Hence, the Lord promises that blessed vision to those who love: "He who loves me will be loved by my Father and I will love him and manifest myself to him" (Jn 14:21). But according to the quantity of his works man merits an accidental reward which is joy taken in those works. Therefore, the apostles performed the works they did with greater charity, which made their hearts prepared for much greater ones, if it had been opportune. 333 678. But if it is said: Someone can try so hard that he will have charity equal to that of the apostles the answer is that a man’s charity is not derived from himself but from God’s grace, which is given to each "according to the measure of Christ’s gift" (Eph 4:7). Now he gives to each the grace proportionate to his calling. Thus, the most excellent grace was given to Christ, because he was called to have his human nature taken into the unity of his divine person; after him the greatest fullness of grace was conferred on blessed Mary, who was called to be the mother of Christ. Among the rest, however, the apostles were called to a greater dignity than all others, for they received from Christ himself the things that pertain to salvation and the commission to deliver them to others. Hence, the Church is in a sense founded on them, as it says in Rev (21:14): "The wall of the city had twelve foundations and on them the twelve names of the twelve apostles of the Lamb." Therefore, God gave them a greater abundance of grace than the rest. 679. Secondly, he mentions the anxiety with which they wait, when he says, we groan inwardly. This groaning indicates the distress caused by the postponement of something desired with great longing, as it says in Pr (13:12); "Hope deferred makes the heart sick"; "I am weary with my moaning" (Ps 6:6). This groaning, however, is more internal than external, because it proceeds from the hidden fee1ings of the heart and because it is concerned with internal goods. Hence he says, we groan inwardly: "My groans are many" (Lam 1:22). 680. Thirdly, he mentions what is awaited, saying: as we wait for adoption as sons, i.e., for the completion of this adoption. For this adoption was begun by the Holy 334 Spirit justifying the soul: "You have received the spirit of adoption as sons" (Rom 8:15). But it will be brought to fulfillment, when the body is glorified: "We rejoice in the hope of sharing the glory of the children of God" (Rom 5:2). And that is why he adds: the redemption of our bodies, so that as our spirit has been redeemed from sin, so our body might be redeemed from corruption and death: "I shall ransom them from death"(Hos 13:14); "He will change our lowly body to be like his glorious body" (Phil 3:21). 681. Then when he says, For in this hope, he proves what he had said with the following reason: Hope is concerned with things not seen in the present but awaited in the future. But we have been saved through hope; therefore, we wait for the completion of salvation as something future. 682. First, therefore, he presents the minor, saying: For we, the apostles and the rest of the believers, were saved in hope, namely, because we hope for our salvation: "We have been born anew to a living hope" (1 Pt 1:3); "Hope in him at all times, O people" (Ps 62:8). 683. Secondly, he presents the major, saying: Now hope, i.e., the thing hoped for, which is seen, as though possessed at present, is not hope, i.e., not something hoped for, but something possessed. For hope is the expectation of something future: "Wait for me, for the day when I arise" (Zeph 3:8). 684. Thirdly, he presents proof of the major, saying: For who hopes for what he sees? As if to say: Hope implies a movement of the soul toward something not possessed. But when something is already possessed, there is no need for one to be moved toward it. 335 And it should be noted that because hope somehow springs from faith, he attributes to hope something that belongs to faith, namely, that it is concerned with something not seen: "Faith is the conviction of things not seen" (Heb 11:1). 685. Fourthly, he presents the conclusion, saying: But if we hope for what we do not see, we wait for it in patience. Hence it should be noted that patience, properly speaking, inclines one to tolerate tribulation with a certain evenness of mind: "Be patient in tribulation" (Rom 12:12). But because the postponement of something good has an aspect of evil, even the continued wait for absent goods with evenness of mind is attributed to patience, although they pertain more to long-suffering; "Be patient, brethren, until the coming of the Lord" (Jas 5:7). But patience is taken in both ways here, because the apostles awaited glory with evenness of mind, along with the delay and tribulation. 686. Then [v. 26; n. 628] he shows how we are helped by the Holy Spirit in the defects of the present life: first, for the fulfillment of desires; secondly, for the direction of external events [v. 28; n. 695]. In regard to the first he does two things: first, he states his proposition; secondly, he clarifies it [v. 26b; n. 688]. 687. First, therefore, he says: It has been stated that our mortal bodies will be vivified by the Holy Spirit, when our weakness shall be removed from us. Likewise in the present life in which we are still subject to weakness the Spirit helps us in our weakness, even though he does not take it away entirely: "The Spirit lifted me up and 336 took me away, and I went in bitterness in the heart of my spirit," as though weakness was not yet entirely removed, "for the hand of the Lord was with me, strengthening me" (Ez 3:14); and in this way he helped me: "The spirit is willing, but the flesh is weak" (Mt 26:41). 688. Then (v. 26b) he clarifies what he had said: first, he shows the need for the Spirit’s help, which pertains to a weakness of the present life; secondly, he indicates the way he helps [v. 26c; n. 692]; thirdly, he shows the efficacy of the help [v. 27; n. 694]. 689. First, therefore, he says: I am correct in saying that the Spirit helps our weakness, for in this we suffer a weakness that we do not know how to pray as we ought: "Why does God surround with darkness the man whose way is hid?" (Jb 3:23). 690. And it should be noted that the Apostle says there are two things we do not know, namely, what we should ask for in prayer and the manner in which we ought to ask [n. 691]. But both seem to be false. For in the first place we know what we should ask for, because the Lord taught us in Mt (6:9): "Hallowed be thy name." The answer is that we can know in a general way what it is suitable to pray for, but we cannot know this in particular. First of all, if we desire to perform a virtuous deed, which is to fulfill God’s will on earth as it is in heaven, it can happen that the virtuous deed does not befit this or that person. For example, the quiet of contemplation is not expedient for a person who can press onward usefully in action, as Gregory says in 337 Morals on Job 5:26: "You shall come to your grave in ripe old age." Hence it says in Pr (14:12): "There is a way which seems right to a man, but its end is the way to death." Secondly, a person desires a temporal good to sustain life, which is to seek one’s daily bread, but it puts him in danger of death. For many have perished because of riches: "Riches were kept by their owner to his hurt" (Ec 5:13). Thirdly, a person desires to be freed from a bothersome trial which, nevertheless, is for him a guardian of humility. For example, St. Paul sought the removal of a thorn of the flesh, but it had been given him to keep him from being too elated by the abundance of revelations, as it says in 2 Cor (12:7). 691. Likewise, it also seems that we know how to pray as we ought, since it says in Jas (1:6): "Let him ask in faith, with no doubting." Here, too, the answer is that we can know in general, but we cannot discern exactly the special motive; for example, whether we are asking from anger or from a zeal for justice. Hence in Mt (20:20) the petition of the sons of Zebedee was refused because, although they seemed to be asking to share in divine glory, their petition proceeded from vain glory or from elation. 692. Then (v.26c) he tells the way the Holy Spirit helps when he says: but the Spirit himself intercedes for us with sighs too keep for words. This statement seems to support the error of Arius and Macedonius, who held that the Holy Spirit is a creature and lower than the Father and Son. For intercession is the role of a lesser person. But if from the fact that he is said to intercede we understand that he is a creature subject to suffering and inferior to the Father, then from the fact that he intercedes with sighs, we should 338 suppose that he is a creature subject to suffering and not yet enjoying beatitude -- which no heretic has ever said. For a sigh proceeds from pain which pertains to wretchedness. Consequently we must explain intercedes [asks], i.e., makes us ask; as in Gen (22:12): "Now I know that you fear God," i.e., I have made you know. 693. For the Holy Spirit makes us ask, inasmuch as he causes right desires in us, because to ask is to make desires known. Now right desires arise from the ardor of love, which he produces in us: "God’s love has been poured into our hearts through the Holy Spirit which has been given to us" (Rom 5:5). But with the Holy Spirit directing and inciting our heart, our desires can not but be profitable to us: "I am the Lord who teaches you to profit" (Is 48:17); therefore, he adds: for us. But when we desire something strongly and pray for it longingly, we suffer its delay with pain and sighing; therefore, he adds: with sighs, which he causes in our heart, inasmuch as he inspires us to desire heavenly things which are postponed for the soul. These are the sighs or moanings of the dove, which the Holy Spirit causes in us: "Moaning like doves" (Nah 2:7). They are indescribable: either because they concern an indescribable thing, namely, heavenly glory: "He heard things that cannot be told" (2 Cor 12:4); or because those movements of the heart cannot be sufficiently described, inasmuch as they proceed from the Holy Spirit: "Who can explain the wisdom of the heavens?" (Jb 38:37). 694. Then (v. 27) he shows the efficacy of the help with which the Holy Spirit aids us, saying: He who searches the hearts, i.e., God, who alone searches the heart: "Thou who tried the minds and hearts" (Ps 7:9). 339 But God is said to search hearts, not as though He investigates the secrets of the heart, but because he knows clearly the hidden things of the heart: "I will search Jerusalem with lamps" (Zeph 1:12). God, I say, searches the hearts and knows, i.e., approves, what is the mind of the Spirit, i.e., what he makes us desire: "All my desires are known to you" (Ps 38:9). But the desires which the Holy Spirit causes in the saints are accepted by God, because the Spirit intercedes for the saints, i.e., makes them ask according to the will of God, i.e., for things pleasing to God: The desire of the righteous ends in all good (Pr 11:23). As an example of this the Lord said to the Father: "Not as I will, but as thou wilt" (Mt 26:39).