Thou shalt increase my greatness - Thou wilt not merely restore me to my former condition, but wilt enlarge my happiness, and wilt do still greater things for me.
And comfort me on every side - literally, "Thou wilt turn thyself; thou wilt comfort me." The word also means to surround; to encompass Genesis 2:11, Genesis 2:13; 1-Kings 7:24; Psalm 18:5; and the idea here may be that God would "go around him," or encircle him, and would thus comfort him. This idea is expressed in our common version. It was the confident assurance of entire, or complete consolation.

Thou shalt increase my greatness - Thou wilt restore me to my throne and kingdom; and it shall be done in such a way that all shall see it was the hand of God; and I shall have the more honor on the account.
Comfort me on every side - I shall have friends in all quarters; and the tribes on all sides will support me.

Thou shalt increase my greatness,.... His temporal greatness, as he did, by crushing the rebellion of his son; returning him to his palace and family; and giving him rest from his enemies all around: and his spiritual greatness, by favouring him with his presence; by shedding abroad his love in his heart; by enlarging his experience; increasing his faith, causing his love to abound, and him to grow in every grace, and in the knowledge of Christ;
and comfort me on every side; by his Spirit, word, and ordinances; by his truths and promises; with his rod and staff; and with mercy, grace, and lovingkindness. The phrase denotes the abundance of comfort, which should come as it were from every quarter, and encompass him about.

increase, &c.--that is, the great things done for me (Psalm 71:19; compare Psalm 40:5).