## When they were ##

"When the Joab and the men of Judah"

## belt ##

a strip of leather or other material used to hold clothing or weapons in place

## sheathed sword ##

This means the sword was in its protective covering.

## the sword fell ##

Joab let the sword fall out to fool Amasa into thinking that he (Joab) was unarmed. Now Joab could get very close to Amasa.