Do not be overly righteous, nor be overly wise. Why be self-destructive?

The words of a wise person win him favor, but the words of a fool are self-destructive.

was it then good that brought death upon me? no, but it was sin, that sin might show it self by being able to bring death upon me by means of that which is good; that sin, I say, by the commandment might appear to be exceedingly destructive.