Albert Barnes Commentary 1 Kings 3:6

"And Solomon said, Thou hast showed unto thy servant David my father great lovingkindness, according as he walked before thee in truth, and in righteousness, and in uprightness of heart with thee; and thou hast kept for him this great lovingkindness, that thou hast given him a son to sit on his throne, as it is this day." — 1 Kings 3:6 (ASV)

This great kindness—David himself had regarded this as God’s crowning mercy to him (1 Kings 1:48).