According to Genesis, God gave a rainbow as the sign of the covenant after the Flood.
Genesis 9:12–17 presents the rainbow as the visible sign of God’s covenant with Noah, his descendants, and every living creature. The covenant promises that a flood will not again destroy all life on earth.
The passage says that when the rainbow appears in the clouds, God will remember the covenant. In this context, the rainbow is not merely a weather observation; it is given a theological meaning within the post-Flood story.
An olive leaf also appears in the account, carried by the dove as evidence that the waters were receding. It is therefore associated with returning land, whereas the rainbow is specifically identified as the covenant sign.