Ge 9:8 Then God spoke to Noah and to his sons with him, saying:

9 "And as for Me, behold, I establish My covenant with you and with your descendants after you,

10 "and with every living creature that is with you: the birds, the cattle, and every beast of the earth with you, of all that go out of the ark, every beast of the earth.

11 "Thus I establish My covenant with you: Never again shall all flesh be cut off by the waters of the flood; never again shall there be a flood to destroy the earth."

12 And God said: "This is the sign of the covenant which I make between Me and you, and every living creature that is with you, for perpetual generations:

13 "I set My rainbow in the cloud, and it shall be for the sign of the covenant between Me and the earth.

14 "It shall be, when I bring a cloud over the earth, that the rainbow shall be seen in the cloud;

15 "and I will remember My covenant which is between Me and you and every living creature of all flesh; the waters shall never again become a flood to destroy all flesh.

16 "The rainbow shall be in the cloud, and I will look on it to remember the everlasting covenant between God and every living creature of all flesh that is on the earth."

17 And God said to Noah, "This is the sign of the covenant which I have established between Me and all flesh that is on the earth."

God made a covenant with Noah and with the animals with him that He would never again destroy earthly life on earth with a flood and He set up a rainbow as a token and sign of the covenant.

Again, this is God showing who's the Boss of the earth. The fact that it was He who assured that the cataclysmic event of a worldwide flood would never ever sweep the whole earth again is a testament to Him being the only Boss of the earth. No other god assures this.