The steps of this degeneracy of the Gentile world as indicated in v. 21–23 may be indicated thus: (1) ceasing to give glory to God and to recognize his power and divineness. (2) Thanklessness. They lost the sense of their relation to him as recipients of his bounty. (3) They entered into vain and foolish speculations—διαλογισμοί. (4) These ended only in blindness of mind and heart to the truth which they once possessed. (5) Mistaking all this folly for wisdom, they were ripe for complete self-deception. They perverted their religious feeling by ceasing to make the glorious perfection of God the object of their worship and by substituting images of men and animals.—G.B.S.