As a matter of self-preservation, a man needs good friends or ardent enemies, for the former instruct him and the latter take him to task.
It was a favorite expression of Theophrastus that time was the most valuable thing that a man could spend.
He has the most who is most content with the least.
Let us not unlearn what we have already learned
We have complicated every simple gift of the gods.
One original thought is worth a thousand mindless quotings