Joshua 1:14 (KJV)

And to the Reubenites, and to the Gadites, and to half the tribe of Manasseh, spake Joshua, saying,

Remember the word which Moses the servant of the Lord commanded you, saying, The Lord your God hath given you rest, and hath given you this land.

Your wives, your little ones, and your cattle, shall remain in the land which Moses gave you on this side Jordan; but ye shall pass before your brethren armed, all the mighty men of valour, and help them;

Until the Lord have given your brethren rest, as he hath given you, and they also have possessed the land which the Lord your God giveth them: then ye shall return unto the land of your possession, and enjoy it, which Moses the Lord’s servant gave you on this side Jordan toward the sunrising.

And they answered Joshua, saying, All that thou commandest us we will do, and whithersoever thou sendest us, we will go.