5 What mean these words, “Glorified Him not as God?” They did not give Him thanks. Is this then to glorify God; to give God thanks? Yes, verily. For what can be worse, if having been created after the image of God, and having come to know God, you shall not be thankful to Him? This surely, this is to glorify God, to give God thanks. The faithful know where and when it is said, “Let us give thanks unto our Lord God.” But who gives thanks to God, save he who “lifts up his heart unto the Lord?” Therefore are they blameable and without excuse, “Because when they knew God, they glorified Him not as God, nor gave Him thanks. But”— what? “But they became vain in their imaginations.” Whence did they become vain, but because they were proud? Thus smoke vanishes away by rising up aloft, and a flame burns the more brightly and strongly in proportion as it is kept low; “They became vain in their imaginations, and their foolish heart was darkened.” So smoke, though it rise higher than the flame, is dark.
Source: Sermons on Selected Lessons of the New Testament (New Advent)