No one in Israel, the sages taught, could humble himself more thoroughly than David when a commandment was at stake. Before God he spoke the words of Psalm 131, and the midrash teaches us how to read each line.
"My heart was not haughty" — this was David when the prophet Samuel anointed him king among his older brothers. He did not lord it over them; he went back to the sheep.
"Nor were my eyes lofty" — this was David when he slew Goliath. He did not walk back to Saul's camp displaying the head like a trophy; he gave the victory to God.
"Neither did I exercise myself in matters too great for me" — this was David when he brought the Ark of the Covenant up to Jerusalem. He did not ride alongside it in royal robes; he danced in a linen ephod, a priest's simple garment.
"Have I not behaved myself, and hushed my soul, as a weaned babe with its mother?" As a small child, unashamed to be undressed before its mother, so I am unashamed to make myself small before You for Your glory.
Recall the moment in 2 Samuel 6:20-21, when David's wife Michal mocked him for dancing "vulgarly" before the servant girls, and David answered her: "I will yet be more vile than this, and will be base in my own sight." The crown, for David, was never higher than the cause of the King of kings.
(From the 1901 Hebraic Literature anthology, drawing on Bamidbar Rabbah 4.)