Adam Clarke on 1 Chronicles 22:1

David said, This is the house of the Lord - Till a temple is built for his name, this place shall be considered the temple of God; and on this altar, and not on that at Gibeon, shall the burnt-offerings of Israel be made. David probably thought that this was the place on which God designed that his house should be built; and perhaps it was this that induced him to buy, not only the threshing-floor, but probably some adjacent ground also, as Calmet supposes, that there might be sufficient room for such a building.