In Genesis, the rainbow represents God’s covenant never again to destroy the earth with a flood.
After Noah leaves the Ark, Genesis describes a covenant between God, Noah, his descendants, and every living creature. God says the rainbow in the clouds will serve as the sign of this promise. Whenever the rainbow appears, the text says, it will recall the covenant and the waters will not again become a flood destroying all life.
The rainbow is therefore distinct from the dove and olive leaf. The dove’s leaf signals that vegetation has returned, while the rainbow is the covenant sign that follows the Flood. The olive branch became a later peace symbol, but it is not the sign named in this passage.
Genesis presents the covenant as universal in scope because it includes animals as well as humans. The story thus links a visible natural phenomenon with a promise about the future of the earth and its living creatures.