The Geneva Bible Translation Notes, [1599], at sacred-texts.com
(a) He means Judah and Benjamin.
He reigned three years in Jerusalem. His mother's name also [was] (b) Michaiah the daughter of (c) Uriel of Gibeah. And there was war between Abijah and Jeroboam.
(b) Or Maacah, (Kg1 15:2).
(c) Called also Absalom, for Absalom was her grandfather, (Kg1 15:2).
And Abijah stood up upon mount (d) Zemaraim, which [is] in mount Ephraim, and said, Hear me, thou Jeroboam, and all Israel;
(d) Which was one of the peaks of mount Ephraim.
Ought ye not to know that the LORD God of Israel gave the kingdom over Israel to (e) David for ever, [even] to him and to his sons by a covenant of salt?
(e) Therefore whoever usurps it or takes it from that stock transgresses the ordinance of the Lord. Thus like a hypocrite he alleges the word of God for his advantage.
And there are gathered unto him (g) vain men, the children of Belial, and have strengthened themselves against Rehoboam the son of Solomon, when Rehoboam was (h) young and tenderhearted, and could not withstand them.
(g) This word in the Chaldee tongue is Racha, which our saviour uses, (Mat 5:22).
(h) Meaning, in heart and courage.
Have ye not cast out the priests of the LORD, the sons of Aaron, and the Levites, and have made you priests after the manner of the nations of [other] lands? so that whosoever cometh to consecrate himself with a (i) young bullock and seven rams, [the same] may be a priest of [them that are] no gods.
(i) He shows the nature of idolaters who take no trial of the calling, life and doctrine of their ministers, but think the most vile and greatest beasts sufficient to serve their turn.
And they burn unto the LORD every (k) morning and every evening burnt sacrifices and sweet incense: the shewbread also [set they in order] upon the pure table; and the candlestick of gold with the lamps thereof, to burn every evening: for we keep the charge of the LORD our God; but ye have forsaken him.
(k) As it was appointed in the law, (Exo 29:39).
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.
But Jeroboam caused an ambushment (m) to come about behind them: so they were before Judah, and the ambushment [was] behind them.
(m) Contemning the good counsel which came from the Spirit of God, he thought to have overcome by deceit.
Thus the children of Israel were brought under at that time, and the children of Judah prevailed, (n) because they relied upon the LORD God of their fathers.
(n) He shows that the stay of all kingdoms and assurance of victories depends on our trust and confidence in the Lord.