Charles Ellicott Commentary Proverbs 20:28

"Kindness and truth preserve the king; And his throne is upholden by kindness." — Proverbs 20:28 (ASV)

Mercy and truth preserve the king.— See above on Proverbs 3:3. The love and faithfulness he shows to his subjects draw out the same qualities in them, and these are the safeguard of his throne. So (Psalms 130:4) the mercy shown by God inspires man with a reverent fear of Him, while harshness might have made him a slave, or driven him through despair into rebellion. (Compare to Jeremiah 33:9.)