And God said, “This is the sign of the covenant I am making between Me and you and every living creature with you, a covenant for all generations to come:
12. This is the token of the covenant . A sign is added to the promise, in which is exhibited the wonderful kindness of God; who, for the purpose of confirming our faith in his word, does not disdain to use such helps.
Articles of agreement among men are usually sealed, that the covenants may be the more solemn, and the performances of the covenants the more sure, to mutual satisfaction. God therefore, being willing more abundantly to show to the heirs of promise the immutability of his councils, has confirmed his covenant by a seal (Heb 6:17), which makes the foundations we build on stand sure, Ti2 2:19.
Commenting on Genesis 9:12-17
And God said, this is the token of the covenant which I make between me and you,.... Meaning the bow in the cloud, and which might be formed in the cloud at this time, that Noah might see it, and know it when he saw it again, and seems to be pointed unto: "this is the token"; or sign of the covenant made between God...