John Gill

And now, O Lord God, thou art that God,.... Who is the Lord of hosts, and the God of Israel, that has promised and is able to perform, and is faithful to his promise: and thy words be true; are truly, punctually, and faithfully performed, never fail: and thou hast promised this goodness unto thy servant; concerning building and establishing his house. David repeats this promise as being greatly affected with it, and fully assured of the performance of it.