What is the literary term for a sentence that contrasts two things with "but" between them. example:A wise son brings honor to his father but a foolish son brings grief to his mother.
It's called antithesis.
Antithesis emphasizes the idea of contrast by parallel structures of the contrasted phrases or clauses, i.e. the structures of phrases and clauses are similar in order to draw the attention of the listeners or readers. - literarydevices.net
The second type of proverb is called antithetical. A thought is given in the first line, and the negative result is given in the second line. In other words, if you do this you’ll be blessed, but if you don’t, this is what will happen to you. So the negative line really accentuates the positive one. - bobyandian.com