Matthew Henry on 2 Chronicles 11:13–end
See here,
I. How Rehoboam was strengthened by the accession of the priests and Levites, and all the devout and pious Israelites, to him, even all that were true to their God and their religion.
1. Jeroboam cast them off, that is, he set up such a way of worship as he knew they could not in conscience comply with, which obliged them to withdraw from his altar, and at the same time he would not allow them to go up to Jerusalem to worship at the altar there; so that he totally cast them off from executing the priest's office, Ch2 11:14. And very willing he was that they should turn themselves out of their places, that room might be made for those mean and scandalous persons whom he ordained pri…
Read the whole note in the consoleJamieson-Fausset-Brown on 2 Chronicles 11:22
made Abijah . . . chief . . . ruler among his brethren--This preference seems to have been given to Abijah solely from the king's doting fondness for his mother and through her influence over him. It is plainly implied that Abijah was not the oldest of the family. In destining a younger son for the kingdom, without a divine warrant, as in Solomon's case, Rehoboam acted in violation of the law (Deu 21:15).
Adam Clarke on 2 Chronicles 11:22
Made Abijah - the chief - Abijah certainly was not the first-born of Rehoboam; but as he loved Maachah more than any of his wives, so he preferred her son, probably through his mother's influence. In Deu 21:16, this sort of preference is forbidden; but Rehoboam had a sort of precedent in the preference shown by David to Solomon.
John Gill on 2 Chronicles 11:22
And Rehoboam made Abijah the son of Maacah the chief,.... The chief of all his sons, head over them, being the son of his most beloved wife, and her firstborn however, and perhaps might be of a greater capacity than the rest of his children:
to be ruler among his brethren; or over them; gave him greater authority, and intrusted him with more power, set him above them, and treated him as heir apparent to the crown: for he thought
to make him king; either to take him into partnership in the throne with him in his lifetime, or to appoint and declare him to be his successor.