Psalms 89:1

I will sing of the mercies of the Lord for ever -Particularly how the “mercy” was manifested in the promise made to David; the solemn covenant made with him in respect to the perpetuity of his throne. The appointment of David to the throne was an act of mere mercy or favor, since he was not in the royal line, and had no claim to the crown. It will be seen, also, that if it be supposed that the covenant with David, and the promise therein made to him, was intended to include the Messiah as descending from him, there was a still higher reason for celebrating the “mercies” of God, inasmuch as all mercy to our world comes through him. With my mouth -Not merely in my heart, but with words.