In the Genesis Flood story, God set a rainbow in the clouds as the covenant sign.
Genesis 9:12–17 describes a covenant between God and Noah, his descendants, and every living creature after the Flood. The rainbow is presented as a visible reminder that the waters would not again become a flood destroying all life. The text calls it a sign of the covenant established after Noah leaves the Ark.
This passage connects the rainbow with a promise involving the whole earth and living creatures, not only Noah’s family. It is one of the reasons the rainbow became a widely recognized symbol of promise, remembrance, and hope in religious and cultural traditions.
The rainbow appears after the Ark narrative’s rescue and repopulation scenes. It is therefore not a feature used to guide the Ark during the storm; Genesis introduces it afterward as a covenant marker. Later artistic depictions often place it over the Ark, but that composition is an interpretive convention.