According to Genesis, God observed the corruption of humanity and decided to cleanse the earth through a great flood, sparing only Noah, a righteous man, and his family.
Noah, following God's detailed instructions, constructed an ark measuring 450 feet long, 75 feet wide, and 45 feet high. He brought aboard pairs of unclean animals and seven pairs of clean animals, along with sufficient food for all. At the age of 600, Noah, his wife, their three sons—Shem, Ham, and Japheth—and their wives entered the ark. For forty days and nights, rain fell, and the waters covered the earth, destroying all life outside the ark.
After the floodwaters recede, God makes a covenant with Noah, promising never again to destroy the earth with a flood, symbolized by a rainbow. Noah and his family, along with the animals, disembark the ark and repopulate the earth after the flood.