en_tn/2sa/20/21.md

has lifted up his hand against

This means to rebel and fight against someone. Alternate translation: "has opposed" or "is rebelling against" (See: rc://en/ta/man/translate/figs-idiom)

Give up him alone

Joab is asking for the people of the city to release Sheba to him. Alternate translation: "Hand this man over to us" or "Give this man to us" (See: rc://en/ta/man/translate/figs-idiom)

I will withdraw from the city

Here the "I" refers to both Joab and his soldiers. Alternate translation: "We will withdraw from the city" (See: rc://en/ta/man/translate/figs-synecdoche)

His head will be thrown

This can be stated in active form. Alternate translation: "We will throw his head" (See: rc://en/ta/man/translate/figs-activepassive)