In Genesis, a rainbow signified God’s covenant after the story of Noah’s Ark.
Genesis 9:12–17 presents the rainbow as the sign of a covenant between God, Noah, and every living creature after the Flood. The covenant promises that a flood will not again destroy all life on earth, and the rainbow is described as a visible reminder of that promise.
The passage frames the covenant as universal in scope: it includes not only Noah and his descendants but also animals and the earth. This is why the rainbow is not merely a private sign for Noah’s family within the narrative.
The biblical account does not explain the rainbow through atmospheric optics. Modern science describes a rainbow as sunlight dispersed and internally reflected by water droplets. The Genesis story instead gives the phenomenon theological meaning within its post-Flood covenant narrative. The symbol has since become important in Jewish, Christian, literary, and broader cultural traditions.