Based on all the marvelous things the Lord has done for them already, God’s children are exhorted to acknowledge his utter uniqueness and obey his commands with the result that this generation and all future generations will experience God’s abundant blessings. Moses challenges his fellow Israelites to “take to heart” or internalize the fact that Yahweh is the universal sovereign (“in heaven above and on the earth below”) and the only sovereign (“there is no other”). In the light of that theological reality, they should gladly obey his commands. Moses affirms that Israel’s genuine obedience to God’s commands will occasion long tenure in the land (and continued enjoyment of covenantal blessings).
Expositor’s Bible Commentary
know … and lay it to your heart. Deuteronomy is constantly concerned with the state of Israel’s heart (see 6:4–5; 7:17; 8:2, 17; 9:4; 10:16).
ESV Study Bible