Numbers 32:20

“And Moses said unto them, etc.] Being better disposed towards them, and more satisfied with the reasonableness of their request, it being explained unto him: if ye will do this thing; which they had promised: if ye will go armed before the Lord to war; they had said they would go ready armed before the children of Israel, but Moses expresses it “before the Lord”; which is more agreeable to their encampment and order in marching, for not the standard of Reuben but that of Judah went foremost, yet the standard of Reuben marched directly before the sanctuary bore by the Kohathites, (<041018>Numbers 10:18,21), and so might be properly said to go before the Lord, who dwelt there.”

“Moses said unto them, If ye will do this thing--with sincerity and zeal. go before the Lord to war--The phrase was used in allusion to the order of march in which the tribes of Reuben and Gad immediately preceded the ark (see on Num. 2:10-31), or to the passage over the Jordan, in which the ark stood in mid-channel, while all the tribes marched by in succession (Jos 3:4), of course including those of Reuben and Gad, so that, literally, they passed over before the Lord and before the rest of Israel (Jos 4:13). Perhaps, however, the phrase is used merely in a general sense to denote their marching on an expedition, the purpose of which was blessed with the presence, and destined to promote the…”

“Before the Lord - Before the ark, which was the token of God's presence. He alludes either to the order of the tribes in their march, whereby Reuben and Gad marched immediately before the ark, or to the manner of their passage over Jordan, wherein the ark went first into Jordan, and stood there while all the tribes marched over Jordan by and before it, and these amongst the rest, as is expressly noted in these very words, that they passed over before the Lord, Jos 4:13. Numbers 32:22”

“32:20-24 Moses accepted the terms offered by Reuben and Gad. If they joined their kindred in fighting the Canaanites, they would fulfill their end of the agreement and could then return to their settlements east of the Jordan (32:22). If they failed to keep their promise, it would be a serious sin against God (32:23).”

“Deu 3:18-20; Jos 1:13-15, Jos 4:12, Jos 4:13, Jos 22:2-4 Numbers 32:22”

“Upon this declaration Moses absolves them from all guilt, and promises them the desired land for a possession, on condition that they fulfil their promise; but he reminds them again of the sin that they will commit, and will have to atone for, if their promise is not fulfilled, and closes with the admonition to build towns for their families and pens for their flocks, and to do what they have promised. Upon this they promise again ( Num 32:25-27), through their spokesman (as the singular ויּאמר in Num 32:25, and the suffix in אדני in Num 32:27, clearly show), that they will fulfil his command. The use of the expression "before Jehovah," in the words, "go armed before Jehovah to war," in Num…”