2 Chronicles 13:1-22

And he reigned for three years in Jerusalem. His mother's name was Michaiah the daughter of Uriel of Gibeah. And there was war between Abijah and Jeroboam (2 Chronicles 13:2).

Now Jeroboam, you remember, was the king of the northern tribes.

And Abijah set the battle in array with an army of valiant men of war, four hundred thousand chosen men: and Jeroboam came against him with eight hundred thousand chosen men, being mighty men of valor. And Abijah stood up upon mount Ephraim, and he said, Hear me, Jeroboam, and all Israel; ought ye not to know that the LORD God of Israel gave the kingdom over Israel to David for ever, even to him and to his sons by a covenant of salt? Yet Jeroboam the son of Nebat, the servant of Solomon the son of David, is risen up, and hath rebelled against his lord. And there are gathered unto him vain men, the children of Belial, who have strengthened themselves against Rehoboam the son of Solomon, when Rehoboam was young and tender-hearted, and could not withstand them. And now you think to withstand the kingdom of the LORD in the hand of the sons of David; and ye be a great multitude, and there are with you golden calves, which Jeroboam made for your gods. And you have 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 comes to consecrate himself with a young bullock and seven rams, the same may be a priest of them that are no gods. But as for us, Jehovah is our God, and we have not forsaken him; and the priests, which minister unto Jehovah, are the sons of Aaron, and the Levites wait upon their business: and they burn unto the LORD every morning and every evening burnt sacrifices and sweet incense: the showbread 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 you have forsaken him. And, behold, God himself is 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 (2 Chronicles 13:3-12).

Here he was actually giving to them a speech, a warning and, more or less, rehearsing this period of history. Again, how that God had made a covenant with David that from his seed there would never cease to be a king on the throne. And they were rebelling against the word of the Lord in setting up Jeroboam as their king. And they had made, then, these golden calves their gods. And they were worshipping them and they had forsaken the worship of God. They began to establish a system of priesthood, more or less, by simony. You could purchase the office of the priest. Vile men began to be the religious leaders. But he said, "We are still worshipping Jehovah. We still have the temple services. The priests are still offering the morning and evening sacrifices unto God, who are the sons of Aaron, the Levitical order. And you're rebelling and fighting against the Lord. But God is our captain. He's on our side."
Now while he's making this speech, Jeroboam orders half of his troops to go around and to get behind them to cut them off. After all, he's outnumbered them two to one. There's eight hundred thousand mighty men of valor with Jeroboam. Only four hundred thousand of the men of Judah that had come against him. So this action of sending half the troops around to come from behind. And so when the king is finished with this dynamic speech, suddenly they discover that the enemy is not only in front of them but behind them, too. And they've been encircled by the enemy.

And then the men of Judah [it says] gave a shout: and as the men of Judah shouted, it came to pass, that God smote Jeroboam and all Israel before Abijah and Judah. And the children of Israel fled before Judah: and God delivered them into their hand. And there were slain of the men of Israel five hundred thousand of the chosen men (2 Chronicles 13:15-17).

So Israel was brought under the power of Judah at that time.

And Abijah pursued after Jeroboam, took several cities, the city of Bethel with the surrounding suburbs. And Jeroboam never did again recover the strength of the kingdom during the time of Abijah: the LORD struck him, and he died. And so Abijah waxed mighty, he married fourteen wives, had twenty-two sons, and sixteen daughters (2 Chronicles 13:19-21). "