I will build thee an house; see Sa2 7:11 , therefore hath thy servant found in his heart to pray this prayer unto thee; found his heart disposed to this service, or found freedom and boldness in him to put up this prayer to God; what encouraged and emboldened him to do it was the gracious promise of God, that he would build up his family, and establish his kingdom; or otherwise he could not have taken such liberty, and used such boldness with God in prayer, as to have requested it of him.