Thematic Bible: Who became vain

This I say therefore, and testify in the Lord, that you no longer walk as the rest of the Gentiles also walk, in the futility of their mind, being darkened in their understanding, alienated from the life of God, because of the ignorance that is in them, because of the hardening of their hearts; who having become callous gave themselves up to lust, to work all uncleanness with greediness.

For the wrath of God is revealed from heaven against all ungodliness and unrighteousness of men, who suppress the truth in unrighteousness, because that which is known of God is revealed in them, for God revealed it to them. For the invisible things of him since the creation of the world are clearly seen, being perceived through the things that are made, even his everlasting power and divinity; that they may be without excuse. read more.
Because, knowing God, they didn't glorify him as God, neither gave thanks, but became vain in their reasoning, and their senseless heart was darkened. Professing themselves to be wise, they became fools, and traded the glory of the incorruptible God for the likeness of an image of corruptible man, and of birds, and four-footed animals, and creeping things.