Genesis 4:17

Now, it is recorded of Cain that he built a city, while Abel, as though he were merely a pilgrim on earth, built none. For the true city of the saints is in heaven, though here on earth it produces citizens in whom it wanders as on a pilgrimage through time looking for the kingdom of eternity. When that day comes, it will gather together all those who, rising in their bodies, shall have that kingdom given to them in which, along with their Prince, the King of Eternity, they shall reign forever and ever.

Consider now the text: "And Cain knew his wife, and she conceived, and brought forth Enoch; and he built a city and called the name thereof by the name of his son Enoch." It does not at all follow from these words that we must believe Cain's first son was Enoch, as though "Cain knew his wife" must refer to their first intercourse. You have the same expression used of the first father, Adam, but not only in reference to the conception of Cain, who seems to have been his firstborn, since a little later Scripture records, "Adam knew his wife, and she conceived and brought forth a son and called his name Seth."

Cain knew his wife, and she conceived and bore Enoch. He built a city, and he called its name after his son's name, Enoch. Just as from the beginning of the world, starting with the murder of Abel, the passions of the saints were present; so too in the malice and persecution of Cain, the betrayals of the reprobate are suggested, which will continue in the world until the end of the age; thus in the city that Cain built, it was symbolically intimated that the entire hope of the wicked is to be fixed on the kingdom and happiness of this world, as they have no faith or desire for future goods. The Lord speaks of this city through the prophet Hosea: "I am God, not human, the Holy One in your midst, and I will not enter into the city" (Hosea 11:9). For neither Abel nor Seth, who was born in his place, are read to have built a city or houses: for they clearly designated, or rather they were the first fruits of those who rejoice to sing to their Creator: "For I am a sojourner with you, a wanderer, as were all my fathers" (Psalm 39:12). This fits well with the promise of the Lord we mentioned earlier: "I am God and not human, the Holy One in your midst": because to the extent that they render themselves foreigners from the association of the worldly city, they are therefore more worthy of the dwelling of their Creator. Cain aptly called the city by the name of his son Enoch, to designate that he would have successors who, being excluded from the heavenly fatherland, would fix their hearts on the delight of this life. And well indeed is Enoch interpreted as Dedication, because the reprobates, while they desire to rejoice for what they work in the present, as if dedicating the city which they build for themselves in the first generation. Conversely, in the lineage of the human race which descended through Seth to Noah, the seventh from Adam is born as Enoch, who is read to have walked before God and was not found because God took him: for indeed the rest and joy and the entire hope of the elect is in the future Sabbath, who, after walking with the Lord in this life, humbly following His commandments, are taken by Him into the life of eternal rest and no longer appear among mortals, because they live with Him immortally. They are indeed His city and temple, now daily striving towards perfection through good works, and then, their labors completed, reigning with Him,…