Ahnsahnghong]-Origin

On the fortieth day after crossing the Red Sea, Moses went up to Mount Sinai for the first time. God spoke to Moses, telling him all of His instructions, and when Moses came down from the mountain he revealed God's will to the people. Ten days later—on the fiftieth day after the Israelites had crossed the Red Sea—Moses returned to Mount Sinai to receive the Ten Commandments. God commanded the people to commemorate the day He had given them the Commandments, the origin of the Feast of Weeks (Ex. 24:1-18).