Chapter 53

David.  Only 6 verses.  Starts with:

1 The fool says in his heart, "There is no God." They are corrupt, doing abominable iniquity; there is none who does good. [Psa 53:1 ESV]

I sure thought that was in chapter 14 of Proverbs, but I cannot find it there.  It is in Psalms 14.1.  The wording I remember is in 14.  This is slightly different, but most certainly has the same idea.