It is unbecoming for young men to utter maxims.
Precepts or maxims are of great weight and a few useful ones on hand do more to produce a happy life than the volumes we can't find.
No matter how full a reservoir of maxims one may possess and no matter how good one's sentiments may be if one has not taken advantage of every concrete opportunity to act one's character may remain entirely unaffected for the better.
I believe there's no proverb but what is true they are all so many sentences and maxims drawn from experience the universal mother of sciences.
In spite of his practical ability some of his experience had petrified into maxims and quotations.