If we say that we haven't sinned, we make him a liar, and his word is not in us.
we make him a liar: That is the worst sin of all. Amos Wilder says: "To go to the length of denying past sin and present guilt is not only to becloud ourselves with sophistry but to give the lie to God Himself" (Coffman 366). God says, "There is none righteous, no, not one," and that "all have sinned" (Romans 3:10; Romans 3:23). Those who profess that they have never sinned, or never sin, make a liar out of God. That is blasphemy!