After the Noah’s Ark flood, God places a rainbow in the cloud as the sign of the covenant.
Genesis 9 describes a covenant with Noah, his descendants, and every living creature after the waters recede. The rainbow serves as a visible reminder of God’s promise never again to destroy all flesh by a flood of that kind.
The passage is more specific than the general idea that a rainbow merely follows rain. In Genesis, it has covenant symbolism and is associated with a divine promise. The covenant extends beyond Noah’s family to animals and the earth.
This rainbow is distinct from the dove that Noah sends earlier to test whether the waters have subsided. The dove is part of the search for dry land; the rainbow appears later as the covenant sign.