Charles Spurgeon Commentary 2 Samuel 7:8-11

"Now therefore thus shalt thou say unto my servant David, Thus saith Jehovah of hosts, I took thee from the sheepcote, from following the sheep, that thou shouldest be prince over my people, over Israel; and I have been with thee whithersoever thou wentest, and have cut off all thine enemies from before thee; and I will make thee a great name, like unto the name of the great ones that are in the earth. And I will appoint a place for my people Israel, and will plant them, that they may dwell in their own place, and be moved no more; neither shall the children of wickedness afflict them any more, as at the first, and [as] from the day that I commanded judges to be over my people Israel; and I will cause thee to rest from all thine enemies. Moreover Jehovah telleth thee that Jehovah will make thee a house." — 2 Samuel 7:8-11 (ASV)

God has a way of returning men's generosity in kind. Since David wished to build God's house, God would build David's house.