Proverbs 27:2 Philosophy

יְהַלֶּלְךָ֣ זָ֣ר וְלֹא־פִ֑יךָ נָ֝כְרִ֗י וְאַל־שְׂפָתֶֽיךָ׃

Let another man praise thee, and not thine own mouth; A stranger, and not thine own lips.

Read Jewish philosophical commentary on Proverbs 27:2: and classical philosophical sources.