Proverbs 16:18

Note, 1. Pride will have a fall. Those that are of a haughty spirit, that think of themselves above what is meet, and look with contempt upon others, that with their pride affront God and disquiet others, will be brought down, either by repentance or by ruin. It is the honour of God to humble the proud, Job 40:11, Job 40:12. It is the act of justice that those who have lifted up themselves should be laid low. Pharaoh, Sennacherib, Nebuchadnezzar, were instances of this. Men cannot punish pride, but either admire it or fear it, and therefore God will take the punishing of it into his own hands. Let him alone to deal with proud men. 2. Proud men are frequently most proud, and insolent, and haughty, just before their destruction, so that it is a certain presage that they are upon the brink of it. When proud men set God's judgments at defiance, and think themselves at the greatest distance from them, it is a sign that they are at the door; witness the case of Benhadad and Herod. While the word was in the king's mouth, Dan 4:31. Therefore let us not fear the pride of others, but greatly fear pride in ourselves.

— Matthew Henry's Concise Commentary (public domain)

(Compare Pro 15:33). Haughtiness and pride imply self-confidence which produces carelessness, and hence a fall--literally, "sliding."

— Jamieson-Fausset-Brown Commentary (public domain)