2 Samuel 15:27-30

The king also said to Zadok the priest, “Do you understand? Go back to the city with my blessing. Take your son Ahimaaz with you, and also Abiathar’s son Jonathan. You and Abiathar return with your two sons. I will wait at the fords in the wilderness until word comes from you to inform me.” So Zadok and Abiathar took the ark of God back to Jerusalem and stayed there. But David continued up the Mount of Olives, weeping as he went; his head was covered and he was barefoot. All the people with him covered their heads too and were weeping as they went up.