20 For where two or three are gathered together in my name, there am I in the midst of them.
[AD 150] Gospel of the Hebrews on Matthew 18:20-21
"If your brother sin against you in word, and make amends to you, receive him seven times in a day." Simon, His disciple, said to Him, "Seven times in a day?" The Lord answered and said to him, "I say unto you until seventy times seven."

[AD 215] Clement of Alexandria on Matthew 18:20
But who are the two or three gathered in the name of Christ in whose midst the Lord is? Does he not by the "three" mean husband, wife, and child? For a wife is bound to her husband by God. If, however, a man wishes to be undistracted, and prefers to avoid begetting children because of the business it involves, "let him remain unmarried," says the apostle, "even as I am." They explain that what the Lord meant was this. By the plurality he means the Creator, the God who is the cause of the world's existence; and by the one, the elect, he meant the Saviour who is Son of another God, the good God. But this is not correct. Through his Son, God is with those who are soberly married and have children. By the same mediation the same God is also with the man who exercises continence on rational grounds.

[AD 220] Tertullian on Matthew 18:20
In a company of two is the church; but the church is Christ.

[AD 220] Tertullian on Matthew 18:20
For if "in the mouth of three witnesses every word shall stand: " -while, through the benediction, we have the same (three) as witnesses of our faith whom we have as sureties of our salvation too-how much more does the number of the divine names suffice for the assurance of our hope likewise! Moreover, after the pledging both of the attestation of faith and the promise of salvation under "three witnesses," there is added, of necessity, mention of the Church; inasmuch as, wherever there are three, (that is, the Father, the Son, and the Holy Spirit, ) there is the Church, which is a body of three.

[AD 220] Tertullian on Matthew 18:20
Where two (are), there withal (is) He Himself. Where He (is), there the Evil One is not.

[AD 220] Tertullian on Matthew 18:20
(The Spirit) combines that Church which the Lord has made to consist in "three." And thus, from that time forward, every number (of persons) who may have combined together into this faith is accounted "a Church," from the Author and Consecrator (of the Church).

[AD 253] Origen of Alexandria on Matthew 18:19-20
And He said not, I will be, but I am in the midst of them; because straightway, as soon as they have agreed together, Christ is found among them.

And this also is the reason why our prayers are not granted, because we do not agree together in all things upon earth, neither in doctrine, nor in conversation. For as in music, unless the voices are in time there is no pleasure to the hearer, so in the Church, unless they are united God is not pleased therein, nor does He hear their words.

Or, In whatever the two testaments are in agreement, for this every prayer is found acceptable to God.

[AD 367] Hilary of Poitiers on Matthew 18:18-20
To hold out a great and terrible fear, by which all men should be reached in this present life, He pronounces that the judgment of the Apostles should be ratified, so that whosoever they bound on earth, i. e. left entangled in the noose of sin, and whosoever they loosed, i. e. accorded the pardon of God's mercy to their salvation, that these should be bound and loosed in heaven.

For He who is peace and charity, will set His place and habitation in good and peaceable dispositions.

[AD 407] John Chrysostom on Matthew 18:18-20
And be it noted, that He said not to the Primate of the Church, Bind such a man; but, If ye shall bind him, the bonds shall be indissoluble; leaving the other to his discretion. And see how He has set the incorrigible person under the yoke of a twofold necessity; to wit, the punishment that is here, namely, the casting forth out of the Church, when He said, Let him be to thee as a heathen; and the future punishment, saying, that he shall be bound in heaven; thus by the weight of his penalties lessening his brother's wrath against him.

Or, because He had said, It shall be done unto them by My Father; therefore, to show that He is the Giver together with His Father, He adds this, where two or three, &c.

Yet He said not barely, Where they are gathered together, but added, in my name, as much as to say, If any man look upon Me as the chief motive of his love to his neighbour, I will be with him, though he is virtue be shown towards other men. How is it then that those who thus agree together do not obtain what they ask for? First, because they ask things not expedient, and because they do not bring on their parts that which they ought to contribute; wherefore He says, If two of you, that is, who show an evangelic conversation. Thirdly, because they pray seeking vengeance against those who have grieved them. And fourthly, because they seek mercy for sinners who have not repented.

[AD 407] John Chrysostom on Matthew 18:18-20
But why did He set him with these? To soothe the person wronged, and to alarm him. Is this only then the punishment? Nay, but hear also what follows. "Whatsoever ye shall bind on earth shall be bound in Heaven." And He did not say to the ruler of the church, "Bind such a man," but, "If thou bind," committing the whole matter to the person himself, who is aggrieved, and the bonds abide indissoluble. Therefore he will suffer the utmost ills; but not he who hath brought him to account is to blame, but he who hath not been willing to be persuaded.

Seest thou how He hath bound him down with twofold constraint, both by the vengeance here, and by the punishment hereafter? But these things hath He threatened, that these circumstances may not arise, but that fearing, at once the being cast out of the church, and the danger from the bond, and the being bound in Heaven, he may become more gentle. And knowing these things, if not at the beginning, at any rate in the multitude of the tribunals he will put off his anger. Wherefore, I tell you, He hath set over him a first, and a second, and a third court, so that though he should neglect to hear the first, he may yield to the second; and even if he should reject that, he may fear the third; and though he should make no account of this, he may be dismayed at the vengeance to come, and at the sentence and judgment to proceed from God.

"And again I say unto you, that if two of you shall agree on earth as touching anything that they shall ask, it shall be done for them of my Father which is in Heaven. For where two or three are gathered together in my name, there am I in the midst of them."

Seest thou how by another motive also He puts down our enmities, and takes away our petty dissensions, and draws us one to another, and this not from the punishment only which hath been mentioned, but also from the good things which spring from charity? For having denounced those threats against contentiousness, He putteth here the great rewards of concord, if at least they who are of one accord do even prevail with the Father, as touching the things they ask, and have Christ in the midst of them.

"Are there then indeed nowhere two of one accord?" Nay, in many places, perchance even everywhere. "How then do they not obtain all things?" Because many are causes of their failing. For either they often ask things inexpedient. And why marvellest thou, if this is the case with some others, whereas it was so even with Paul, when he heard, "My grace is sufficient for thee; for my strength is perfected in weakness." Or they are unworthy to be reckoned with them that heard these words, and contribute not their own part, but He seeks for such as are like them; therefore He saith "of you," of the virtuous, of them that show forth an angelic rule of life. Or they pray against them that have aggrieved them, seeking for redress and vengeance; and this kind of thing is forbidden, for, "Pray," saith He, "for your enemies." Or having sins unrepented they ask mercy, which thing it is impossible to receive, not only if themselves ask it, but although others having much confidence towards God entreat for them, like as even Jeremiah praying for the Jews did hear, "Pray not thou for this people, because I will not hear thee."

But if all things are there, and thou ask things expedient, and contribute all thine own part, and exhibit an apostolical life, and have concord and love towards thy neighbor, thou wilt obtain on thy entreaty; for the Lord is loving towards man.

Then because He had said, "Of my Father," in order that He might show that it is Himself that giveth, and not He who begat Him only, He added, "For wheresoever two or three are gathered together in my name, there am I in the midst of them."

What then? are there not two or three gathered together in His name? There are indeed, but rarely. For not merely of the assembling doth He speak, neither this doth He require only; but most surely, as I said before also, the rest of virtue too together with this, and besides, even this itself He requires with great strictness. For what He saith is like this, "If any holds me the principal ground of his love to his neighbors, I will be with Him, if he be a virtuous man in other respects."

But now we see the more part having other motives of friendship. For one loves, because he is loved, another because he hath been honored, a third because such a one has been useful to him in some other worldly matter, a fourth for some other like cause; but for Christ's sake it is a difficult thing to find any one loving his neighbor sincerely, and as he ought to love him. For the more part are bound one to another by their worldly affairs. But Paul did not love thus, but for Christ's sake; wherefore even when not loved in such wise as he loved, he did not cease his love, because he had planted a strong root of his affection; but not so our present state, but on inquiry we shall find with most men anything likely to produce friendship rather than this. And if any one bestowed on me power in so great a multitude to make this inquiry, I would show the more part bound one to another by worldly motives.

[AD 420] Jerome on Matthew 18:19-20
(Verse 19, 20.) Again I say to you: if two of you agree on earth about anything they ask, it will be done for them by my Father in heaven. For where two or three are gathered in my name, there am I among them. The above discourse has encouraged us towards harmony. Therefore, it promises a reward so that we may hasten eagerly towards peace, as it says that it will be present among two or three. Similar to the example of a tyrant, who wanted to prove that he had captured two friends (when one returned to see his mother and gave his friend as a surety for himself), so he wanted to test one, and release the other. And when he returned on the appointed day, marveling at the faith of both, he asked that they have a third. We can also understand this spiritually, that where the spirit and soul and body agree and do not have war between themselves of different desires (or pleasures); with the flesh desiring against the spirit, and the spirit against the flesh, they obtain from the Father whatever they seek about any thing. And there is no doubt that the request of good things is certain, where the body wants to have those things which the spirit wants.

[AD 420] Jerome on Matthew 18:18-20
Because He had said, If he will not hear the Church, let him be to thee as a heathen, and a publican, whereupon the brother so contemned might answer, or think within himself, If you despise me, I also will despise you; if you condemn me, you shall be condemned by my sentence. He therefore confers powers upon the Apostles, that they may be assured that when any are condemned after this manner, the sentence of man is ratified by the sentence of God. Verily I say unto you, Whatsoever ye shall bind on earth shall be bound in heaven; and whatsoever ye shall loose upon the earth shall be loosed in heaven.

Or otherwise; All His foregoing discourse had invited us to union; now to make us embrace peace more anxiously, He holds out a reward, promising to be in the midst of two or three.

(vid. Origen. in loc.) We may also understand this spiritually; where our spirit, soul, and body are in agreement, and have not within them conflicting wills, they shall obtain from My Father every thing they shall ask; for none can doubt that that demand is good, where the body wills the same thing as the spirit.

[AD 430] Augustine of Hippo on Matthew 18:18-20
(ubi sup.) Otherwise; When you begin to hold your brother as a publican you bind him on earth, but take heed that you bind him with just cause; for an unjust cause breaks rightful bonds. But when you have corrected him, and agreed with him, you have loosed him upon earth, and when you have loosed him upon earth, he shall be loosed also in heaven. You confer a great boon not on yourself, but on him, as he had done the hurt not to you but to himself.

[AD 444] Cyril of Alexandria on Matthew 18:20
Christ gives to those who are allotted the duty of teaching the power to loose and to bind. So when those who have once fallen do not convert to the pursuit of virtue, they must fear the voices of the saints, even if they are not many who make the petition to bind or loose. For Christ has assured us of this, saying that there will be strength in the prayers of many, but that even if only two in number harmoniously and deliberately define their requests, they will come to their goal. “For I will be with you,” he says, “and will support you if only two are gathered, because of me.” For it is not the number of those gathered but the strength of their piety and their love of God that is effective.

[AD 450] Peter Chrysologus on Matthew 18:20
There are those who presume that the congregation of the church can be disregarded. They assert that private prayers should be preferred to those of an honorable assembly. But if Jesus denies nothing to so small a group as two or three, will he refuse those who ask for it in the assemblies and congregation of the church? This is what the prophet believed and what he exults over having obtained when he states, “I will confess to you, O Lord, with my whole heart, in the council and congregation of the righteous.” A man “confesses with his whole heart” when in the council of the saints he hears that everything which he has asked will be granted him.Some, however, endeavor to excuse under an appearance of faith the idleness that prompts their contempt for assemblies. They omit participation in the fervor of the assembled congregation and pretend that they have devoted to prayer the time they have expended upon their household cares. While they give themselves up to their own desires, they scorn and despise the divine service. These are the people who destroy the body of Christ. They scatter its members. They do not permit the full form of its Christ-like appearance to develop to its abundant beauty—that form which the prophet saw and then sang about: “You are beautiful in form above the sons of men.”
Individual members do indeed have their own duty of personal prayer, but they will not be able to fulfill it if they come to the beauty of that perfect body wrapped up in themselves. There is this difference between the glorious fullness of the congregation and the vanity of separation that springs out of ignorance or negligence: in salvation and honor the beauty of the whole body is found in the unity of the members. But from the separation of the viscera there is a foul, fatal and fearful aroma.

[AD 1107] Theophylact of Ohrid on Matthew 18:20
. By these words He draws us together in love. After forbidding us to give offence to each other, either to harm and to be harmed, now He speaks of mutual agreement and harmony. Those who agree are those who collaborate, not in evil, but in good. Mark what He said: "if two of you," that is, of believers who are virtuous. For Annas and Caiaphas also agreed, but in a manner deserving blame. This is why we often pray but do not receive, because we do not agree among each other. He did not say, "I will be there," for He does not merely intend to be there at some future time, nor does He delay, but rather He said, "there am I," that is, I am present at once. You may also understand that when the flesh and the spirit agree, and the flesh does not desire something in opposition to the spirit, then is the Lord there in the midst. And so also do the three faculties of the soul — the abilities to reason, to be stirred to action, and to desire — all agree. But the Old and the New agree as well and Christ is in their midst, proclaimed by both.
[AD 1274] Glossa Ordinaria on Matthew 18:18-20
(ap. Anselm.) But He holds out a ratification not only of sentences of excommunication, but of every petition which is offered by men holding together in the unity of the Church; for He adds, Again I say unto you, that if two of you shall agree upon earth, whether in admitting a penitent, or casting out a forward person, touching any thing which they shall ask, any thing, that is, that is not against the unity of the Church, it shall be done for them by my Father which is in heaven. By saying, which is in heaven, He points Him out as above all, and therefore able to fulfil all that shall be asked of Him. Or, He is in the heavens, that is, with saints, proof enough that whatever worthy thing they shall ask shall be done unto them, because they have with them Him of whom they ask. For this cause is the sentence of those that agree together ratified, because God dwells in them, For where two or three are gathered together in my name, there am I in the midst of them.