NOTES for Sa2 7:28
So exclaims King David, having received the prophecy about the coming Messiah. For him it is completely obvious that if God has promised something, then it is already as good as present, because God's words are unchangeable. Is there such faith in God in us, such trust in Him? We read many wonderful promises of God in the Old Testament and especially in the New Testament. Do we accept them as something unchangeable, or do we treat them as something conditional: perhaps it will happen, and perhaps it will not? We even find a kind of "justification" for this unbelief: "But we are sinners; how can we receive what was promised?"
Yes, but David too was a sinner, and yet he did not doubt the truth of God's promise. And again we can recall Jesus' words filled with bitterness: "Nevertheless, when the Son of Man comes, will He find faith on earth?"