[wyattearp]

"If you seek revenge, first dig two graves."

I heard another one:

"Two wrongs don't make a right, but the second one evens the score".

[Feiny]

I remember a hard core metal song with these lyrics:

"Two wrongs don't make a right, but it makes me feel a whole lot better".

[Feiny]

I just remembered....the group was Suicidal Tendencies.

They say two wrongs don't make a right
Well maybe that is true
But I can't describe the feeling I get
When I take revenge on you

[HKMk23]

Try this on for size:

"To him who knows the good he ought to do and does not do it, to him it is sin."

Protecting the young by jackin' up a would-be perp is a good thing, and I'll be among the last to sin by failing to do it.

[Snardius]

"Two wrongs don't make a right, but the second one evens the score".

An eye for an eye leaves everyone blind.