Which rainbow-related promise does God make after Noah leaves the Ark?

After Noah leaves the Ark, God promises never again to destroy all life by a flood.

Genesis 9 describes a covenant between God, Noah, his descendants, and every living creature. God sets the rainbow in the clouds as the sign of this covenant and says that the waters will never again become a flood to destroy all flesh. The promise concerns a world-destroying flood, not the end of all rain or every local flood.

The covenant follows Noah’s altar sacrifice after leaving the ark and is presented as universal in scope because it includes animals as well as people. The rainbow’s role in Genesis is therefore specifically covenantal. Later biblical passages use rainbows in other symbolic contexts, but those references do not replace the promise made in Genesis 9.