CCC 2482 “A lie consists in speaking a falsehood with the intention of deceiving.”1 The Lord denounces lying as the work of the devil: “You are of your father the devil,. .. 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.”2
1 St. Augustine, De mendacio 4, 5: PL 40: 491.
2 Jn 8:44.