From the Bible, Proverbs 24:17-18:
17 Do not gloat when your enemy falls; when they stumble, do not let your heart rejoice
18 or the Lord will see and disapprove and turn his wrath away from them.
Or else you could just ignore the Good Book:
When it comes to Commies, Greens, hypocrites and the like tripping on their own dicks / getting hoist by their own petard etc., I’m afraid I am very much of the latter persuasion.
One of the few side benefits of being an atheist, I guess.