Jamieson, Fausset and Brown on 2 Samuel 15:30

30. David went up by the ascent of mount Olivet--The same pathway over that mount has been followed ever since that memorable day.

had his head covered--with a mourning wrapper. The humility and resignation of David marked strongly his sanctified spirit, induced by contrition for his transgressions. He had fallen, but it was the fall of the upright; and he rose again, submitting himself meekly in the meantime to the will of God [Chalmers].