In the Genesis flood story, a rainbow was the sign of God’s covenant with Noah.
Genesis 9 describes God’s covenant with Noah, his descendants, and every living creature after the flood. The rainbow is placed in the clouds as a sign that the covenant will be remembered. The associated promise is that the waters will not again become a flood destroying all flesh.
The rainbow appears after Noah leaves the Ark and builds an altar. Genesis 9 expands the covenant beyond Noah’s household to animals and the earth. This makes the sign part of a universal post-flood promise within the narrative, not merely a private marker for Noah.
The rainbow is often confused with the dove carrying an olive leaf. The dove episode occurs earlier, in Genesis 8, when Noah tests whether the waters have receded. The bird is a sign of emerging dry land; the rainbow is the covenant sign stated in Genesis 9. These are distinct events and symbols.