This is a summary of the agreement made and described in Numbers 32:20 — -32. (See also Note on Joshua 1:12.)
Related Commentaries of Deuteronomy 3:18
Deuteronomy 3:18-19
18 And I commanded you at that time, saying, The LORD your God hath given you this land to possess it: ye shall pass over armed before your brethren the children of Israel, all that are meetb for the war.
19 But your wives, and your little ones, and your cattle, (for I know that ye have much cattle,) shall abide in your cities which I have given you;