Musannaf Ibn Abi Shayba 33:947

Ubayd Allah ibn Musa narrated to us, he said: Salih al-Fazari informed us, from Ibrahim ibn Maymun, from Wahb ibn Munabbih, who said: Dawud (David) said: "O Lord, the son of Adam has not a single hair except that beneath it is a blessing from You, and above it is a blessing from You. So how can he compensate You for what You have given him?" He said: So Allah revealed to him: "O Dawud, I give much and I am satisfied with little. And the gratitude for that to Me is that he knows that whatever blessing he has is from Me."