There is not a single ill-doer who could not be turned to some good.

He that does good to another, does good also to himself, not only in the consequences, but in the very act; for the consciousness of well doing is, in itself, ample reward.

For naught so vile that on the earth doth live But to the earth some special good doth give ...

The best is enemy of the good.

Do all the good you can, In all the ways you can, In all the places you can, At all the times you can, To all the people you can, As long as ever you can.