Orchot Tzadikim
There is another joy whose effect is as bitter as wormwood — for instance the joy of those who pursue immorality and robbery and all other sins and rejoice when they attain their evil lusts. Concerning these it is said: "Who rejoice to do evil and delight in the forwardness of evil" (Prov. 2:14). Their guilt is great and brings them to the lowest pit.