Notes on the Bible, by Albert Barnes, , at sacred-texts.com
The events of this chap. are no doubt recorded in their proper historical order. The auxiliary forces of the trans-Jordanic tribes were not sent away immediately after the campaigns against the Canaanites were over. They set forth from Shiloh, Jos 22:9, to which place the sanctuary had been removed Jos 18:1 after the conquest and the settlement of the children of Judah and of Joseph in their possessions, and after the appointment of the Levitical cities.
The insertion of this explanation about the half tribe, and the repetition of Joshua's farewell, are examples of a marked characteristic of very ancient writers and of Hebrew writers as much as any - that of giving a completeness and finish to each section of their story. The Jewish historian scarcely ever quotes or reminds, but repeats so much as may be necessary to make his account of the transaction in hand fully intelligible by itself. (Compare also Jos 13:14, Jos 13:33; Jos 14:3; Jos 18:7.) It is quite possible, however, that the particulars special to Jos 22:8, may be due to some other narrative of the whole event than that to which Jos 22:5 belongs, and may have been interwoven by a later reviser.
Gilead - Here used in the widest sense for the whole trans-Jordanic district.
The two tribes and a half erected this altar in order to keep alive their claim to have the same interest as the other tribes had in the sanctuary of God, which was established on the west side of Jordan: and in order to forestall any assertion that the Jordan itself was a natural barrier of exclusion between them and the sanctuary, they built it on the west or Canaanite bank of the Jordan and not on the east.
The word rendered "borders" is noteworthy; it means circuits, arrondissements.
Gathered themselves together - The various tribes had already dispersed to their homes, and were now summoned together again.
From which we are not cleansed until this day - Phinehas, who had borne a conspicuous part in vindicating the cause of God against those who fell away to Baal-peor, means that terrible as the punishment had been, there were still those among them who hankered after Baal worship, and even practiced it in secret. (Compare Joshua's words, Jos 24:14-23.)
Unclean - i. e. unholy because the sanctuary was not in it, but on the other side of Jordan.
The repeated invocation of God, and that by His three names - אל 'êl, אלהים 'ĕlohı̂ym, יהוה yehovâh: compare Psa 50:1 - marks the earnestness of the protestation. The conduct of the two tribes and a half has often been noted as exemplary. They had had a grave and capital crime most unexpectedly laid to their charge, of which they were entirely innocent. Yet there is no word of reproach or recrimination in their vindication of themselves. They are contented simply to repudiate the false accusation and to explain the real motives of conduct perhaps suggested to them by a precedent set by Moses Exo 17:15.
Save us not this day - The words are a direct appeal to God, exactly equivalent in effect to our form "So help me God."
The word עד ‛êd is not found after "altar" in the text of most manuscripts, nor is it represented in the Septuagint or Vulgate. The passage should probably run: "the children of Reuben and the children of Gad named the altar, that (as they said) it might be, etc." The title placed on the altar was perhaps simply a witness between them that the Lord was God (Wordsworth).