Abijah’s direct quotation at this point may be difficult to avoid. It continues until the end of verse 12. His speech to the Israelite troops was intended to win them over to worship the true God and avoid actual bloodshed.
Ought you not to know…? is literally “Is it not for you to know…?” but this question is more clearly translated “Don’t you know…?” (New International Version) or “Don’t you realize…?” (New Living Translation). In any case, the question is rhetorical and may have to be translated in other languages as “Surely you know…,” “You must know…” (Die Bibel im heutigen Deutsch), or “You should know…” (New Century Version). Abijah’s question assumes that Jeroboam and his soldiers should know that God made an unbreakable covenant with David to rule over Israel.
That the LORD God of Israel gave the kingship over Israel for ever to David and his sons: Sons in this context clearly refers to “descendants” (Good News Translation, Bible en français courant, Die Bibel im heutigen Deutsch) or “dynasty” ( NET Bible). The meaning of this whole clause will be more naturally expressed in some languages as “that the LORD God of Israel made David and his descendants rulers over Israel forever” or “… caused David and his descendants to always rule over Israel.”
By a covenant of salt: For covenant see the comments on 1 Chr 11.3. According to Lev 2.13, every offering that was a grain offering was to be salted. Salt preserved and purified (see 2 Kgs 2.19-22). A covenant of salt means the covenant was unbreakable (compare Num 18.19). Good News Translation and New Living Translation say “an unbreakable covenant,” Die Bibel im heutigen Deutsch has “an irrevocable covenant” (similarly Bible en français courant), and Moffatt translates “an irrevocable pledge.” If the meaning of this expression is not made clear in translation, an explanatory footnote stating that it refers to a very solemn and unchangeable promise will be necessary.
Quoted with permission from Omanson, Roger L. and Ellington, John E. A Handbook on 1-2 Chronicles, Volume 1. (UBS Helps for Translators). Miami: UBS, 2014. For this and other handbooks for translators see here .