Psalms 61:6

“Thou wilt prolong the King’s life, etc.] Or “add days to the days of the King” f821. Meaning either himself, who, though his life was in danger by fighting with the Syrians and Edomites, or rather through the conspiracy of his son; yet was assured that he should yet live many years more, and especially in his posterity; and that his kingdom would be established for ever, as was promised him, (<100712>2 Samuel 7:12-16). Or rather the King Messiah, so the Targum: and Kimchi observes, that if this psalm respects the captivity, the King is the King Messiah: it may be understood of his life as man; who, though he died, rose again, and lives for evermore; and that, as to the glory of God the…”

“the king--himself and his royal line ending in Christ. Mercy and truth personified, as in Psa 40:11; Psa 57:3.”

“Thou wilt prolong the king’s life - literally, “Days upon the days of the king thou wilt add;” that is, Thou wilt add days to those which thou hast already permitted him to live. The language does not necessarily mean that he would have a long life, but that he would still be permitted to live. He had apprehended death. He knew that his life was sought by those who were engaged with Absalom in the rebellion. At first it was uncertain what the issue would be. He had fled for his life. But now, in answer to prayer, he felt assured that his life would be preserved; that he would be permitted to return to his home and his throne; and that as king - as the sovereign of his people - he would be…”

“Prolong - The years of my life and reign. Thus he speaks because his kingdom was not like Saul's, but established to him and his heirs; and because Christ, his son and heir, should actually, and in his own person possess the kingdom for ever. Psalms 61:7”

“wilt prolong the king's life: Heb. shalt add days to the days of the king, Psa 21:4, Psa 21:6, Psa 72:15-17; Isa 53:10 many generations: Heb. generation and generation, Psa 89:36, Psa 89:37 Psalms 61:7”