Numbers 1:45

So were all those that were numbered ^{H6485} of the children ^{H1121} of Israel ^{H3478}, by the house ^{H1004} of their fathers ^{H1}, from twenty ^{H6242} years ^{H8141} old ^{H1121} and upward ^{H4605}, all that were able to go forth ^{H3318} to war ^{H6635} in Israel ^{H3478};

counted the people of Isra'el by their clans, those twenty years old and over, eligible for military service in Isra'el;

So all the Israelites twenty years of age or older who could serve in Israel’s army were counted according to their families.

So all they that were numbered of the children of Israel by their fathers’ houses, from twenty years old and upward, all that were able to go forth to war in Israel;