Wait -- In what legal way are Christians doing as you describe, by referencing/discussing/adhering to what is written and believed among the Hebrews from ages ago ??
Do you see what is recorded, in context ?? "it will be a sign of the covenant between Me and the earth" / "
between Me and you and every living creature of every kind. Never again will the waters become a flood to destroy all life"
8Then God said to Noah and his sons with him,
9“Behold, I now establish My covenant with you and your descendants after you,
10and with every living creature that was with you—the birds, the livestock, and every beast of the earth—every living thing that came out of the ark.
11And I establish My covenant with you: Never again will all life be cut off by the waters of a flood; never again will there be a flood to destroy the earth.”
12And 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:
13I have set My rainbow in the clouds, and it will be a sign of the covenant between Me and the earth.
14Whenever I form clouds over the earth and the rainbow appears in the clouds,
15I will remember My covenant between Me and you and every living creature of every kind. Never again will the waters become a flood to destroy all life.
16And whenever the rainbow appears in the clouds, I will see it and remember the everlasting covenant between God and every living creature of every kind that is on the earth.”
17So God said to Noah, “This is the sign of the covenant that I have established between Me and every creature on the earth.”