In the Genesis Ark story, God placed a rainbow in the cloud as the sign of the covenant with Noah.
Genesis 9 describes a covenant made after Noah and his family leave the Ark. God promises that a flood will not again destroy all flesh, and the rainbow becomes the visible reminder of that promise. The covenant extends beyond Noah’s household: the text speaks of every living creature and all future generations.
The rainbow therefore appears after the Flood narrative’s rescue and sacrifice scenes. It is not the object that guides the Ark, and it is not the bird Noah sends to test whether the waters have receded. Those are separate details in the story.
Genesis presents the rainbow as a sign already visible in the natural world but given a specific covenant meaning in the narrative. Its role is memorial and symbolic: whenever the cloud and rainbow appear, the covenant is remembered.