Joshua 22:3
Ye have not left your brethren these many days unto this day, but have kept the charge of the commandment of the LORD your God. Ye have not left your brethren these many days unto this day, but have kept the charge of the commandment of the LORD your God.
The verse is Joshua's commendation of Gad and Reuben and half Manasseh for faithfully keeping their pledge to their brethren. Those tribes had chosen their inheritance east of the Jordan in the grazing lands of Gilead and Bashan. In return they had promised to send their armed men across the Jordan to fight with the other tribes until Canaan was taken.
Forty thousand of them passed over to the plains of Jericho and fought bravely beside their brethren for years. Only when that work was finished were they released to return to their own possession. They returned with much riches, cattle, silver, gold, brass, iron, and raiment to share with those who had stayed behind with the families and flocks.
Their departure was watched with an anxious heart. Dwelling far from the sanctuary in isolation would expose them to temptation to follow the customs of the bordering heathen tribes.