And thus do you find with Yonadav. In the beginning he was called "Yehonadav," but after "that deed" a letter was dropped from his name and he was called "Yonadav," as it is written (II Chronicles 20:37) "When you befriended Achazyahu, etc." — whence the sages ruled: Let one not befriend an evildoer, even to draw him close to Torah.