To be ruler among his brethren; he declared him his successor, and gave him the dominion over his brethren; wherein (if he was not the first-born, as it seems to be implied, because this is mentioned as an effect of his superlative love to his mother) he transgressed that law, Deuteronomy 21:15,16, unless God was pleased to dispense with it at this time.
Related Commentaries of 2 Chronicles 11:22
2 Chronicles 11:22
22 And Rehoboam made Abijah the son of Maachah the chief, to be ruler among his brethren: for he thought to make him king.