Proverbs 27

Proverbs 27:2

Let another praise you, and not your own mouth;
A stranger, and not your own lips.

Yet another verse that gives a clue how to find the truth in one's heart.  Lots of people "toot their own horn," as the old saying goes.  They declare themselves good, or right, or superior.  But self-affirmation is often the most unreliable form there is.

At the same time, this doesn't say to belittle oneself.  It says to let someone else praise you, not you yourself.  It doesn't say that instead you should criticize or downplay yourself.  I've heard that humility is thinking of yourself less, not less of yourself.  This verse, I believe, matches with that.