II Chronicles 11, Rehoboam, King of Two Tribes

Jeroboam and the northern tribes have rebelled from Rehoboam.

2 Chronicles 11: 1-4, March north on Israel?

When Rehoboam arrived in Jerusalem, he mustered the house of Judah and Benjamin--a hundred and eighty thousand fighting men--to make war against Israel and to regain the kingdom for Rehoboam. But this word of the LORD came to Shemaiah the man of God: "Say to Rehoboam son of Solomon king of Judah and to all the Israelites in Judah and Benjamin, This is what the LORD says: Do not go up to fight against your brothers. Go home, every one of you, for this is my doing.'" 

So they obeyed the words of the LORD and turned back from marching against Jeroboam. 

Benjamin, always adjacent physically to Judah, stays with Rehoboam.

Rehoboam wants to march on Israel but is persuaded not to do that by the prophet Shemaiah. If the people of Judah march on Israel, they are going into the face of God's plans. (Payne suggests that the "180,000 fighting men" might really be translated "180 chiefs" but also argues that the figure 180,000 is plausible.)

Shemaiah will be described as one who wrote records of this time, see 2 Chronicles 12: 15.

2 Chronicles 11: 5-12, Fortified cities

Rehoboam lived in Jerusalem and built up towns for defense in Judah: Bethlehem, Etam, Tekoa, Beth Zur, Soco, Adullam, Gath, Mareshah, Ziph, Adoraim, Lachish, Azekah, Zorah, Aijalon and Hebron. These were fortified cities in Judah and Benjamin.

He strengthened their defenses and put commanders in them, with supplies of food, olive oil and wine. He put shields and spears in all the cities, and made them very strong. So Judah and Benjamin were his.
 

Faced with a smaller kingdom, Rehoboam fortifies a variety of towns around Judah and Benjamin. 

2 Chronicles 11: 13-17, Levites and others Israelites move south

The priests and Levites from all their districts throughout Israel sided with him. The Levites even abandoned their pasturelands and property, and came to Judah and Jerusalem because Jeroboam and his sons had rejected them as priests of the LORD. And he appointed his own priests for the high places and for the goat and calf idols he had made.

Those from every tribe of Israel who set their hearts on seeking the LORD, the God of Israel, followed the Levites to Jerusalem to offer sacrifices to the LORD, the God of their fathers. They strengthened the kingdom of Judah and supported Rehoboam son of Solomon three years, walking in the ways of David and Solomon during this time.

 

Jeroboam rejects the worship of YHWH in Jerusalem and sets up various idols and appoints his own priests, rejecting the role of the Levites. Levites living in the northern kingdom fleeing south to Judah, along with others who had set their hearts on YHWH.  

2 Chronicles 11: 18-21, Mahalath, Maacah and more

Rehoboam married Mahalath, who was the daughter of David's son Jerimoth and of Abihail, the daughter of Jesse's son Eliab. She bore him sons: Jeush, Shemariah and Zaham. 

Then he married Maacah daughter of Absalom, who bore him Abijah, Attai, Ziza and Shelomith. Rehoboam loved Maacah daughter of Absalom more than any of his other wives and concubines. In all, he had eighteen wives and sixty concubines, twenty-eight sons and sixty daughters.
 

Mahalath is a granddaughter of Eliab, brother of David.   Maacah is the granddaughter of Absalom, David's son.  So Mahalath and Rehoboam had a common great grandfather, Jesse; Maacah and Rehoboam had a common grandfather, David. Rehoboam's other sixteen wives are unnamed, but in the culture of the day, especially for one who ruled a kingdom, Rehoboam has many wives and concubines and thus many sons and daughters.

2 Chronicles 11: 22-23, Abijah

Rehoboam appointed Abijah son of Maacah to be the chief prince among his brothers, in order to make him king. He acted wisely, dispersing some of his sons throughout the districts of Judah and Benjamin, and to all the fortified cities. He gave them abundant provisions and took many wives for them.

Abijah, son of Maacah is appointed to be the next king; it is possible that for a time there was a coregency with Abijah ruling with his elderly father.