וַיֵּ֤דַע קַ֙יִן֙ אֶת־אִשְׁתּ֔וֹ וַתַּ֖הַר וַתֵּ֣לֶד אֶת־חֲנ֑וֹךְ וַֽיְהִי֙ בֹּ֣נֶה עִ֔יר וַיִּקְרָא֙ שֵׁ֣ם הָעִ֔יר כְּשֵׁ֖ם בְּנ֥וֹ חֲנֽוֹךְ׃
And Cain knew his wife; and she conceived, and bore Enoch; and he builded a city, and called the name of the city after the name of his son Enoch.
Read kabbalistic (mystical) interpretation of Genesis 4:17: and classical mystical sources.