In the Book of Genesis, the rainbow was the sign of God’s covenant with Noah after the Flood.
Genesis 9:12–17 presents the rainbow as a visible reminder of the covenant between God, Noah, every living creature, and the earth. The covenant promises that a flood will not again destroy all flesh or devastate the earth in the same way.
The rainbow appears after Noah leaves the ark and builds an altar. Genesis describes the covenant as extending beyond Noah’s family to animals and future generations. This makes the sign broader than a private promise to one household.
The dove and olive leaf belong to the earlier process of discovering that the waters had receded. They are not the covenant sign named in Genesis 9. Likewise, the altar is an act of worship, while the rainbow is the sign associated with the covenant itself.