Never ask pardon before you are accused proverb
Saying sorry for something wrong you did before someone has blamed it on you will only make them think, know that you are the one responsible for it. But if you don't, you can get away with it.
Though I broke vase, I didn't tell my mom about it because I thought to myself "never ask pardon before you are accused".
A: You had better admit having torn his book and apologize to him. B: No, I will wait until he ask me. Never ask pardon before you are accused, you know.
The origin of this proverb is not clear.