(ubi sup.) By which words He seems to show clearly enough that the foregoing discourse was the last that He spake to them upon earth, though it does not appear to bind us down altogether to this opinion. For He does not say, After He had thus spoken unto them, wherefore it admits of being understood not as if that was the last discourse, but that the words which are here used, After the Lord had spoken unto them, he was received into heaven, might belong to all His other discourses. But since the arguments which we have used above make us rather suppose that this was the last time, therefore we ought to believe that after these words, together with those which are recorded in the Acts of the Apostles, our Lord ascended into heaven.
(de Symbolo, 4) Let us not therefore understand this sitting as though He were placed there in human limbs, as if the Father sat on the left, the Son on the right, but by the right hand itself we understand the power which He as man received from God, that He should come to judge, who first had come to be judged. For by sitting we express habitation, as we say of a person, he sat himself down in that country for many years; in this way then believe that Christ dwells at the right hand of God the Father. For He is blessed and dwells in blessedness, which is called the right hand of the Father; for all is right hand there, since there is no misery. It goes on: And they went forth and preached every where, the Lord working with than, and confirming the word with signs and wonders.
(Epist. cxcix. 12.) (Acts 1:8) But how was this preaching fulfilled by the Apostles, since there are many nations in which it has just begun, and others in which it has not yet begun to be fulfilled? Truly then this precept was not so laid upon the Apostles by our Lord, as though they alone to whom He then spoke were to fulfil so great a charge; in the same way as He says, Behold, I am with you always, even unto the end of the world, apparently to them alone; but who does not understand that the promise is made to the Catholic Church, which though some are dying, others are born, shall be here unto the end of the world?
(ubi sup.) Are we then without faith because we cannot do these signs? Nay, but these things were necessary in the beginning of the Church, for the faith of believers was to be nourished by miracles, that it might increase. Thus we also, when we plant groves, pour water upon them, until we see that they have grown strong in the earth; but when once they have firmly fixed their roots, we leave off irrigating them. These signs and miracles have other things which we ought to consider more minutely. For Holy Church does every day in spirit what then the Apostles did in body; for when her Priests by the grace of exorcism lay their hands on believers, and forbid the evil spirits to dwell in their minds, what do they, but cast out devils? And the faithful who have left earthly words, and whose tongues sound forth the Holy Mysteries, speak a new language; they who by their good warnings take away evil from the hearts of others, take up serpents; and when they are hearing words of pestilent persuasion, without being at all drawn aside to evil doing, they drink a deadly thing, but it will never hurt them; whenever they see their neighbours growing weak in good works, and by their good example strengthen their life, they lay their hands on the sick, that they may recover. And all these miracles are greater in proportion as they are spiritual, and by them souls and not bodies are raised.
(ubi sup.) We have seen in the Old Testament that Elias was taken up into heaven. But the ethereal heaven is one thing, the aerial is another. The aerial heaven is nearer the earth, Elias then was raised into the aerial heaven, that he might be carried off suddenly into some secret region of the earth, there to live in great calmness of body and spirit, until he return at the end of the world, and pay the debt of death. We may also observe that Elias mounted up in a chariot, that by this they might understand that a mere man requires help from without. But our Redeemer, as we read, was not carried up by a chariot, not by angels, because He who had made all things was borne over all by His own power. We must also consider what Mark subjoins, And sat at the right hand of God, since Stephen says, I see the heavens opened, and the Son of Man standing at the right hand of God. Now sitting is the attitude of a judge, standing of one fighting or helping. Therefore Stephen, when toiling in the contest, saw Him standing, whom he had for his helper; but Mark describes Him as sitting after His assumption into heaven, because after the glory of His assumption, He will in the end be seen as a judge.
(ubi sup.) But what should we consider in these words, if it be not that obedience follows the precept and signs follow the obedience? For the Lord had commanded them, Go into all the world preaching the Gospel, and, Ye shall be witnesses even unto the ends of the earth.
(ubi sup.) Observe that in proportion as Mark began his history later, so he makes it reach in writing to more distant times, for he began from the commencement of the preaching of the Gospel by John, and he reaches in his narrative those times in which the Apostles sowed the same word of the Gospel throughout the world.
But we must also know from this that words are confirmed by deeds as then in the Apostles works confirmed their words, for signs followed. Grant then, O Christ, that the good words which we speak may be confirmed by works and deeds, so that at the last, Thou working with us in word and in deed, we may be perfect, for Thine as is fitting is the glory both of word and deed. Amen.
The Lord Jesus, who had descended from heaven to give liberty to our weak nature, Himself also ascended above the heavens; wherefore it is said, So then after the Lord had spoken unto them, he was received up into heaven.
Let us draw near, then, my beloved, to faith, since its powers are so many. For faith raised up [Enoch] to the heavens, and overcame the deluge. It caused the barren to bring forth. It delivered from the sword. Faith raised up from the pit. It enriched the poor. It released the captives. It delivered the persecuted. It brought down the fire. It divided the sea. Faith cleft the rock and gave to the thirsty water to drink. It satisfied the hungry. It raised the dead and brought them up from Sheol. It stilled the billows. It healed the sick.
But they, having departed, preached everywhere, with the Lord working with them and confirming the word with the accompanying signs. What is to be considered in this, what to be commended to memory, except that they followed the command with obedience, and obedience was followed by signs? Among these, it is notable that Mark, although he began his Gospel later than the others, extended it to longer times in his writing. For he neither mentioned the birth of the Lord himself or his forerunner, nor any account of their infancy or childhood, nor did he write in depth about the birth of the Savior, except that he called him the Son of God at the beginning of his Gospel. He began from the start of the evangelical preaching, which happened through John, and continued narrating up to the time when the apostles disseminated the entire Gospel word by preaching around the world.
[AD 430] Augustine of Hippo on Mark 16:19-20
(de Symbolo, 4) Let us not therefore understand this sitting as though He were placed there in human limbs, as if the Father sat on the left, the Son on the right, but by the right hand itself we understand the power which He as man received from God, that He should come to judge, who first had come to be judged. For by sitting we express habitation, as we say of a person, he sat himself down in that country for many years; in this way then believe that Christ dwells at the right hand of God the Father. For He is blessed and dwells in blessedness, which is called the right hand of the Father; for all is right hand there, since there is no misery. It goes on: And they went forth and preached every where, the Lord working with than, and confirming the word with signs and wonders.
(Epist. cxcix. 12.) (Acts 1:8) But how was this preaching fulfilled by the Apostles, since there are many nations in which it has just begun, and others in which it has not yet begun to be fulfilled? Truly then this precept was not so laid upon the Apostles by our Lord, as though they alone to whom He then spoke were to fulfil so great a charge; in the same way as He says, Behold, I am with you always, even unto the end of the world, apparently to them alone; but who does not understand that the promise is made to the Catholic Church, which though some are dying, others are born, shall be here unto the end of the world?