God sees that the wickedness of man is great in the earth and that the earth is filled with violence. He is grieved in His heart. “But Noah found grace in the eyes of the LORD.” Noah was a just man and he walked with God.
God tells Noah to build an ark of gopherwood and gives him exact measurements. Noah does “according to all that God commanded him, so he did.” Into the ark go Noah, his wife, his three sons — Shem, Ham and Japheth — their wives, and the animals God brings. Then the LORD shuts them in.
It rains upon the earth forty days and forty nights, and the waters cover even the mountains. Yet Genesis 8 begins with these tender words: “Then God remembered Noah.” The waters go down, and the ark rests upon the mountains of Ararat. Noah sends out a raven, and then a dove, which returns with an olive leaf in her mouth.
When Noah comes out, the first thing he does is build an altar and worship. God makes a covenant never again to destroy the earth with a flood, and He sets His rainbow in the cloud as the sign of that covenant. Every rainbow is a reminder that God keeps His promises.