Numbers 1:3 (King James Version)
3 From twenty years old and upward, all that are able to go forth to war in Israel: thou and Aaron shall number them by their armies.
Numbers 1:20 (King James Version)
20 And the children of Reuben, Israel's eldest son, by their generations, after their families, by the house of their fathers, according to the number of the names, by their polls, every male from twenty years old and upward, all that were able to go forth to war;
Numbers 1:45 (King James Version)
45 So were all those that were numbered of the children of Israel, by the house of their fathers, from twenty years old and upward, all that were able to go forth to war in Israel;