Hippolytus of Rome

Observe that the wise man must be useful to many; so that he who is useful only to himself cannot be wise. For great is the condemnation of wisdom if she reserves her power simply for the one possessing her. But as poison is not injurious to another body, but only to that one which takes it, so also the man who turns out wicked will injure himself, and not another. For no man of real virtue is injured by a wicked man.

Hippolytus Exegetical Fragments ↗