John Calvin Commentary Numbers 15:41

"I am Jehovah your God, who brought you out of the land of Egypt, to be your God: I am Jehovah your God." — Numbers 15:41 (ASV)

I am the Lord your God. Having at the end of the last verse commanded them to be holy to their God, He now confirms this command with a reason, namely, that it was for this purpose that God redeemed them: that He might be their God, that is, that He might be solemnly honored. He asserts God’s right, then, as founded on the blessing of their deliverance, which would have been in vain unless they devoted themselves to His service. The repetition at the conclusion is intended for confirmation.