What does it mean to hold the truth down in unrighteousness?
It means suppressing and trampling the truth, which may be understood as Jesus Christ Himself. People have the knowledge of God but reject it, refusing His words and this Book, holding Him underfoot rather than wanting Him in their lives.
Les teaches that in the New Testament, whenever you see the word "truth," you can very easily substitute the name of Jesus Christ, because He said, "I am the truth, the way and the life." So holding the truth down in unrighteousness means taking the name of Jesus Christ and holding it down in ungodliness. They do not want anything He had to say, or anything that comes from this Book, in their lives, so they hold it underfoot. Les explains that God has still made the knowledge of Himself manifest in them; the invisible things of Him from the creation of the world are clearly seen, so that they are without excuse.
For the wrath of God is revealed from heaven against all ungodliness and unrighteousness of men, who hold the truth in unrighteousness;