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.
Related Commentaries of Psalms 61:6
Psalms 61:6
6 Thou wilt prolong the king's life: and his years as many generations.