And the children of Reuben and the children of Gad called the altar Ed: for it shall be a witness between us that the LORD is God.

Wesley's Notes

22:34 The altar Ed - That is, a witness: a witness of the relation they stood in to God and Israel, and of their concurrence with the other tribes in the common faith, that Jehovah he is God. It was a witness to posterity, of their care to transmit their religion pure and entire; and would be a witness against them, if ever they should turn from following the Lord their God.

King James Translators' Notes

Ed: that is, A witness

Scofield Reference Notes

Margin Ed

i.e. a witness; Song Josh 24:27.

Matthew Henry's Concise Commentary

22:30-34 It is well that there was on both sides a disposition to peace, as there was a zeal for God; for quarrels about religion, for want of wisdom and love, often prove the most fierce and difficult to be made up. Proud and peevish spirits, when they have passed any unjust blame on their brethren, though full evidence be brought of its unfairness, can by no means be persuaded to withdraw it. But Israel was not so prejudiced. They looked upon their brethren's innocence as a token of God's presence. Our brethren's zeal for the power of godliness, and faith and love, notwithstanding the fears of their breaking the unity of the church, are things of which we should be very glad to be satisfied. The altar was called ED, a witness. It was a witness of their care to keep their religion pure and entire, and would witness against their descendants, if they should turn from following after the Lord. Happy will it be when all professed Christians learn to copy the example of Israel, to unite zeal and steady adherence to the cause of truth, with candour, meekness, and readiness to understand each other, to explain and to be satisfied with the explanations of their brethren. May the Lord increase the number of those who endeavour to keep the unity of the Spirit in the bond of peace! may increasing grace and consolation be with all who love Jesus Christ in sincerity!