Asahel the brother of Joab was one of the thirty; Elhanan the son of Dodo of Beth-lehem,

Asael the brother of Joab was one of the thirty, Elehanan the son of Dodo of Bethlehem.

Asahel, the brother of Joab, was one of the thirty; and Elhanan, the son of Dodai, of Beth-lehem,

Among the thirty were: Asahel, the brother of Joab, Elhanan, the son of his paternal uncle, from Bethlehem,

etc. The early death of Asahel 2-Samuel 2:32 would make it very likely that his place in the 30 would be filled up, and so easily account for the number 31 in the list. Compare throughout the list in 1 Chr. 11.

Asahel - was one of the thirty - Asahel was one of those officers, or troops, called the shalishim. This Asahel, brother of Joab, was the same that was killed by Abner, 2-Samuel 2:23.

Asahel the brother of Joab was one of the thirty,.... Or rather over the thirty (n), who are next mentioned; since there are thirty reckoned besides him, and the Arabic version calls him the prince of the thirty; Joab is not named at all, because he was general of the whole army, and so not to be reckoned in any of the three classes:
Elhanan the son of Dodo of Bethlehem: a townsman of David.
(n) "supra triginta istos", Junius & Tremellius.