Then David knew that the Lord had established him as king over Israel and had exalted his kingdom for the sake of his people Israel.
NMVAnd David [beloved] perceived that the LORD-Yehōvah (Messiah Pre-Incarnate) had established him king over Yisra’el [He Holds Onto The Heel Of God], and that he had exalted his kingdom for his people Yisra’el’s [He Holds Onto The Heel Of God] sake.
OJBAnd Dovid had da'as that Hashem had established him Melech Yisroel, and that he had exalted his mamlachah for the sake of His people Yisroel.
T4THis doing that caused David to realize that Yahweh truly had appointed him to be the king of Israel, and that Yahweh was going to cause his kingdom to prosper, because Yahweh loved the Israeli people, whom he had chosen to belong to him.