Numbers 33:39 in the King James Version
And Aaron was an hundred and twenty and three years old when he died in mount Hor.
Context
38 Aaron the priest went up into Mount Hor at the commandment of the LORD and died there, in the fortieth year after the children of Israel had come out of the land of Egypt, in the fifth month, on the first day of the month.
39 Aaron was one hundred twenty-three years old when he died in Mount Hor.
40 The Canaanite king of Arad, who lived in the South in the land of Canaan, heard of the coming of the children of Israel.