1 Corinthians 15:47

Paul is referring here to the second coming of Christ.

The first decree commanded to increase and to multiply; the second enjoined continency. While the world is still rough and void, we are propagated by the fruitful begetting of numbers, and we increase to the enlargement of the human race. Now, when the world is filled and the earth supplied, they who can receive continency, living after the manner of eunuchs, are made eunuchs unto the kingdom. Nor does the Lord command this, but He exhorts it; nor does He impose the yoke of necessity, since the free choice of the will is left. But when He says that in His Father's house are many mansions, He points out the dwellings of the better habitation. Those better habitations you are seeking; cutting away the desires of the flesh, you obtain the reward of a greater grace in the heavenly home. All indeed who attain to the divine gift and inheritance by the sanctification of baptism, therein put off the old man by the grace of the saving layer, and, renewed by the Holy Spirit from the filth of the old contagion, are purged by a second nativity. But the greater holiness and truth of that repeated birth belongs to you, who have no longer any desires of the flesh and of the body. Only the things which belong to virtue and the Spirit have remained in you to glory. It is the apostle's word whom the Lord called His chosen vessel, whom God sent to proclaim the heavenly command: "The first man," says he, "is from the earth, of earth; the second man is from heaven. Such as is the earthy, such are they also who are earthy; and such as is the heavenly, such also are the heavenly. As we have borne the image of him who is earthy, let us also bear the image of Him who is heavenly." Virginity bears this image, integrity bears it, holiness bears it, and truth. […]

Vices and carnal sins must be trampled down, beloved brethren, and the corrupting plague of the earthly body must be trodden under foot with spiritual vigour, lest, while we are turned back again to the conversation of the old man, we be entangled in deadly snares, even as the apostle, with foresight and wholesomeness, forewarned us of this very thing, and said: "Therefore, brethren, let us not live after the flesh; for if ye live after the flesh, ye shall begin to die; but if ye, through the Spirit, mortify the deeds of the flesh, ye shall live. For as many as are led by the Spirit of God they are the sons of God." If we are the sons of God, if we are already beginning to be His temples, if, having received the Holy Spirit, we are living holily and spiritually, if we have raised our eyes from earth to heaven, if we have lifted our hearts, filled with God and Christ, to things above and divine, let us do nothing but what is worthy of God and Christ, even as the apostle arouses and exhorts us, saying: "If ye be risen with Christ, seek those things which are above, where Christ is sitting at the right hand of God; occupy your minds with things that are above, not with things which are upon the earth. For ye are dead, and your life is hid with Christ in God. But when Christ, who is your life, shall appear, then shall ye also appear with Him in glory." Let us, then, who in baptism have both died and been buried in respect of the carnal sins of the old man, who have risen again with Christ in the heavenly regeneration, both think upon and do the things which are Christ's, even as the same apostle again teaches and counsels, saying: "The first man is of the dust of the earth; the second man is from heaven. Such as he is from the earth, such also are they who are from the earth and such as He the heavenly is, such also are they who are heavenly. […]

That Christ is both man and God, compounded of both natures, that He might be a Mediator between us and the Father. In Jeremiah: "And He is man, and who shall know Him? Also in Numbers: "A Star shall arise out of Jacob, and a man shall rise up from Israel." Also in the same place: "A Man shall go forth out of his seed, and shall rule over many nations; and His kingdom shall be exalted as Gog, and His kingdom shall be increased; and God brought Him forth out of Egypt. His glory is as of the unicorn, and He shall eat the nations of His enemies, and shall take out the marrow of their fatnesses, and will pierce His enemy with His arrows. He couched and lay down as a lion, and as a lion's whelp. Who shall raise Him up? Blessed are they who bless Thee, and cursed are they who curse Thee." Also in Isaiah: "The Spirit of the Lord is upon me; on account whereof He hath anointed me: He hath sent me to tell good tidings to the poor; to heal the bruised in heart, to preach deliverance to the captives, and sight to the blind, to proclaim the acceptable year of the Lord, and the day of retribution." Whence, in the Gospel according to Luke, Gabriel says to Mary: "And the angel, answering, said to her, The Holy Ghost shall come upon thee, and the power of the Highest shall overshadow thee. Wherefore that holy thing which is born of thee shall be called the Son of God." Also in the first Epistle of Paul to the Corinthians: "The first man is of the mud of the earth; the second man is from heaven. As was he from the soil, such are they also that are of the earth; and as is the heavenly, such also are the heavenly. As we have borne the image of him who is of the earth, let us also bear the image of Him who is from heaven."

That he who has attained to trust, having put off the former man, ought to regard only celestial and spiritual things, and to give no heed to the world which he has already renounced. In Isaiah: "Seek ye the Lord; and when ye have found Him, call upon Him. But when He hath come near unto you, let the wicked forsake his ways, and the unrighteous man his thoughts: and let him be turned unto the Lord, and he shall obtain mercy, because He will plentifully pardon your sins." Of this same thing in Solomon: "I have seen all the works which are done under the sun; and, lo, all are vanity." Of this same thing in Exodus: "But thus shall ye eat it; your loins girt, and your shoes on your feet, and your staves in your hands: and ye shall eat it in haste, for it is the Lord's passover." Of this same thing in the Gospel according to Matthew: "Take no thought, saying, What shall we eat? or, What shall we drink? or, Wherewith shall we be clothed? for these things the nations seek after. But your Father knoweth that ye have need of all these things. Seek first the kingdom of God, and His righteousness; and all these things shall be added unto you." Likewise in the same place: "Think not for the morrow, for the morrow shall take thought for itself. Sufficient unto the day is its own evil." Likewise in the same place: "No one looking back, and putting his hands to the plough, is fit for the kingdom of God." Also in the same place: "Behold the fowls of the heaven: for they sow not, nor reap, nor gather into barns; and your heavenly Father feedeth them. Are not ye of more value than they? " Concerning this same thing, according to Luke: "Let your loins be girded, and your lamps burning; and ye like unto men that wait for their lord, when he cometh from the wedding; that, when he cometh and knocketh, they may open to him. […]

Having said that "the natural was first," and "the spiritual afterward," he again states another difference, speaking of "the earthy" and "the heavenly." For the first difference was between the present life and that which is to come: but this between that before grace and that after grace. And he stated it with a view to the most excellent way of life, saying, (for to hinder men, as I said, from such confidence in the resurrection as would make them neglectful of their practice and of perfection, from this topic also again he renders them anxious and exhorts to virtue, saying,) "The first man is of the earth, earthy; the second man is the Lord from heaven:" calling the whole by the name of "man," and naming the one from the better, and the other from the worst part.

The first man Adam was made a living soul, the last Adam was made a quickening Spirit. Howbeit that was not first which is spiritual, but that which is natural, and afterwards that which is spiritual; and then he adds, The first man is of the earth, earthy, the second man is from heaven, heavenly.

Lest they grow negligent regarding the beautiful life, he now wishes to persuade them toward a God-pleasing life, and says that Adam was from the earth, from which he was also so named; for Adam means earthly and dusty. But the second man was the …

995. – He assigns the reason for what is said about diversity, saying, the first man. As if to say: truly the first man was made a living animal, because he is of the earth: "God formed man of dust from the ground" (Gen. 2:7), …

He himself made the heavens, and by descending from thence showed himself to us as the Lord. Christ was not the second man in order of time; but in this respect, that as Adam was a public person, who acted in the stead of all mankind, so was Christ. As Adam was the first general representative of men, Christ was the second and the last.

Humanity in Christ is generic. In Him man is impersonated in his true ideal as God originally designed him. Christ is the representative man, the federal head of redeemed man.

The first man is of the earth - That is: Adam’s body was made out of the dust of the earth; and hence the apostle says he was χοΐκος, of the dust; for the body was made עפר מן האדמה aphar min haadamah, dust from the ground; Gen 2:7. The second man is - from heaven - Heavenly, ουρανιος, as several good MSS. and versions read. The resurrection body shall be of a heavenly nature, and not subject to decay or death. What is formed of earth must live after an earthly manner; must be nourished and supported by the earth: what is from heaven is of a spiritual nature; and shall have no farther connection with, nor dependence upon, earth. I conceive both these clauses to relate to man; and to point out the difference between the animal body and the spiritual body, or between the bodies which we now have and the bodies which we shall have in the resurrection. But can this be the meaning of the clause, the second man is the Lord from heaven? In the quotation I have omitted ὁ Κυριος, the Lord, on the following authorities: Manuscripts - BCD*EFG, and two others. Versions - Coptic, Ethiopic, Armenian in the margin, Vulgate, and Itala. Fathers-Origen, who quotes it once and omits it once; Athanasius, Basil, the two Gregories, Nyssen and Nazianzen; Isidore, Cyril, Tertullian, Cyprian, Hilary, Zeno, Ambrose, Augustine, Jerome, Ambrosiaster, Philaster, Leo, Pacianus, Primasius, Sedulius, Bede, and others. See these authorities more at large in Wetstein. Some of the most eminent of modern critics leave out the word, and Tertullian says that it was put in by the heretic Marcion. I do think that the word is not legitimate in this place. The verse is read by the MSS., versions, and fathers referred to, thus: The first man is of the earth, earthy; the second man is of heaven, heavenly; Κυριος being omitted and ουρανιος added. […]

The first man - Adam. Is of the earth - Was made of the dust; see Gen 2:7. Earthy - Partaking of the earth; he was a mass of animated clay, and could be appropriately called “dust;” Gen 3:19. Of course, he must partake of a nature that was low, mean, mortal, and corruptible. The second man - Christ; see the note on 1Co 15: