Komentarz do Diwrej ha-jamim I 16:15

Remember His covenant forever And in Psalms: “He remembered His covenant forever.” The meaning is: The covenant that He made with Abraham - He remembered it forever and for His children, and that which He spoke to him and the promise that He promised him, He commanded that it stand to the thousandth generation. Or the meaning of צִוָּה is גָזַר decreed, like (Lam. 3:37): “... unless the Lord ordained it (צִוָּה).” The meaning is that the word that He decreed [in the Covenant] Between the Parts to give the land of Canaan to their children will be to the thousandth generation, and that which He says here: “Remember,” means: His covenant that is with you forever - remember it constantly.