Japheth was one of three sons of Noah, the righteous man whose family God saved from the great flood.
Hundreds of years after God created the world, man had fallen into such a state of depravity that “the Lord regretted that he had made human beings on the earth, and his heart was deeply troubled” (Genesis 6:6). There was one righteous man named Noah, and the Lord commanded him to build an ark so his family would be saved. After bringing two of every unclean animal and seven of every clean animal to the ark, the Lord shut the door and sent the rains (Genesis 7:13–16). Noah; his wife; his sons, Shem, Ham, and Japheth; and their wives were saved.
When the flood waters subsided and Noah’s family exited the ark, God commanded them to repopulate the earth. Noah began to tend the ground and grow a vineyard, but there is not much more said about Shem, Ham, or Japheth except in the account of Noah’s drunkenness in Genesis 9:20–27. This passage describes a day Noah became drunk on the wine from his vineyard and passed out naked in his tent. Ham found Noah in that shameful condition and told Shem and Japheth what he had seen (verse 22). Shem and Japheth brought in a garment and, walking backward so they wouldn’t shame their father by looking at his nakedness, covered Noah with the garment (verse 23). When Noah woke, he cursed Ham but blessed Shem and Japheth (verses 24–27). Japheth’s blessing took the form of these words: “May God extend Japheth’s territory; / may Japheth live in the tents of Shem, / and may Canaan [Ham’s son] be the slave of Japheth” (verse 27).
After the flood, Japheth and his brothers did indeed multiply and repopulate the earth. Japheth himself fathered seven sons: Gomer, Magog, Madai, Javan, Tubal, Meshech, and Tiras (Genesis 10:2). The descendants of Japheth included various maritime peoples (verse 5) as well as the Persians, Greeks, Romans, Scythians, and Macedonians. Japheth’s descendants spread out over much of Asia and Europe and, through colonization, North America, thus fulfilling Noah’s prediction of “expansion” for Japheth.