Jesus said, "You are of your father the devil, and your will is to do your father's desires. He was a murderer from the beginning, and has nothing to do with the truth, because there is no truth in him. When he lies, he speaks according to his own nature, for he is a liar and the father of lies."
Where does this saying of Jesus come from? I've decided to present a paper on it at SBL in New Orleans.