The captains refers to the officers mentioned in verse 4, who were over the Carites and the guards.

The Hebrew verbs translated go off duty and come on duty have already been dealt with in verses 5 and 7.

The repetition of Jehoiada the priest may be considered redundant and unnecessary in some languages. Note that Good News Translation replaces the second occurrence of this phrase with the pronoun “him.” Even where the proper name is repeated, it may be superfluous to add the qualifying words the priest (see the comments on verse 4). This verse may also require some restructuring to make it flow more naturally in certain languages (so Good News Translation).

Quoted with permission from Omanson, Roger L. and Ellington, John E. A Handbook on 1-2 Kings, Volume 2. (UBS Helps for Translators). New York: UBS, 2008. For this and other handbooks for translators see here .