Numbers 1:26,27 (KJV)
26 Of the children of Judah, by their generations, after their families, by the house of their fathers, according to the number of the names, from twenty years old and upward, all that were able to go forth to war;
27 Those that were numbered of them, even of the tribe of Judah, were threescore and fourteen thousand and six hundred.
Numbers 1
War And The Minimum Age To Join
The age requirement to join an army was given by God thousands of years ago. We now keep to an age requirement today in our armies.