Matthew Henry Commentary Psalms 80:17-19

"Let thy hand be upon the man of thy right hand, Upon the son of man whom thou madest strong for thyself. So shall we not go back from thee: Quicken thou us, and we will call upon thy name. Turn us again, O Jehovah God of hosts; Cause thy face to shine, and we shall be saved." — Psalms 80:17-19 (ASV)

The Messiah, the Protector and Savior of the church, is the Man of God's right hand; He is the Arm of the Lord, for all power is given to Him. In Him is our strength, by which we are enabled to persevere to the end. The vine, therefore, cannot be ruined, nor can any fruitful branch perish; but the unfruitful will be cut off and cast into the fire. The end of our redemption is that we should serve Him who has redeemed us, and not go back to our old sins.