I don’t mind citing a bad author if the line is good.

Levity of behavior is the bane of all that is good and virtuous.

What need is there to weep over parts of life? The whole of it calls for tears.

What-so-ever the mind has ordained for itself, it has achieved

My joy in learning is partly that it enables me to teach.

The place one's in, though, doesn't make any contribution to peace of mind: it's the spirit that makes everything agreeable to oneself.

Only a great man, believe me, and one whose excellence rises far above human failings, will not allow anything to be stolen from his own span of time, and his life is very long precisely because he has devoted to himself entirely any time that became available. None of it lay uncultivated and idle, none was under another man's control, for guarding it most jealously, he found nothing worth exchanging for his own precious time.