12 Behold, God is with us at our head, and his priests with the trumpets of alarm to sound an alarm against you. Children of Israel, don't fight against Yahweh, the God of your fathers; for you shall not prosper."
*Minor differences ignored. Grouped by changes, with first version listed as example.
God himself is with us - Ye have golden calves; we have the living and omnipotent Jehovah.
With - trumpets to cry alarm against you - This was appalling: When the priests sound their trumpets, it will be a proof that the vengeance of the Lord shall speedily descend upon you.
And, behold, God himself [is] (l) with us for [our] captain, and his priests with sounding trumpets to cry alarm against you. O children of Israel, fight ye not against the LORD God of your fathers; for ye shall not prosper.
(l) Because their cause was good and approved by the Lord, they did not doubt the success and victory.
And, behold, God himself is with us for our Captain,.... To go before our armies, and fight our battles for us:
and his priests with sounding trumpets to cry alarm against you; which was one use of the trumpets, that the people might be remembered by the Lord, and saved from their enemies, Numbers 10:9, so that this circumstance was against Jeroboam and his army, and for Abijah and his:
O children of Israel, fight ye not against the Lord God of your fathers; for fighting against his people, that retained the pure worship of him, was fighting against him:
for you shall not prosper; he seems to be assured of victory.
Abijah draws from all this the conclusion: "Behold, with us at our head are (not the two calves of gold, but) God (האלהים with the article, the true God) and His priests, and the alarm-trumpets to sound against you." He mentions the trumpets as being the divinely appointed pledges that God would remember them in war, and would deliver them from their enemies, Numbers 10:9. Then he closes with a warning to the Israelites not to strive with Jahve, the God of their fathers.
Trumpets - Upon the sounding whereof God hath solemnly promised to assist his people, Numbers 10:9. The Lord - You have not only us for your enemies, but God, even the God whom your fathers served. It is folly to fight against the God of almighty power: but it is treachery and base ingratitude, to fight against your father's God.
*More commentary available at chapter level.