en_tn/2ch/12/01.md

It came about

This phrase is used here to mark the beginning of a new part of the story. If your language has a way for doing this, you could consider using it here.

when Rehoboam's reign was established

This can be translated in active form. Alternate translation: "when Rehoboam had established his reign" (See: rc://en/ta/man/translate/figs-activepassive)

all Israel with him

Here the words "all Israel" refer specifically to the people of the tribes of Judah and Benjamin, over which Rehoboam was king. The verb may be supplied from the previous phrase. Alternate translation: "all the Israelite people whom he ruled also abandoned the law of Yahweh" (See: rc://en/ta/man/translate/figs-metonymy and rc://en/ta/man/translate/figs-ellipsis)