en_tn/2sa/18/02.md

one-third ... another third

"one-third of the army ... another third of the army." A "third" is one part out of three equal parts. (See: rc://en/ta/man/translate/translate-fraction)

Abishai ... Zeruiah

See how you translated these men's names in 2 Samuel 2:18. (See: rc://en/ta/man/translate/translate-names)

Ittai

See how you translated this man's name in 2 Samuel 15:19. (See: rc://en/ta/man/translate/translate-names)

Gittite

This refers to a person from Gath, which is a Philistine city. (See: rc://en/ta/man/translate/translate-names)

I will certainly go out with you myself, too

This means that he will go out with them to battle. This can be stated clearly. Alternate translation: "I myself will go with you to battle" or "I personally will go with you into battle" (See: rc://en/ta/man/translate/figs-explicit)