What does Judges 20:16 mean?
The people of Benjamin have decided to stand against all the other tribes of Israel. Men of the town of Gibeah (Judges 19:14) committed a horrific atrocity (Judges 19:22–27). The rest of Israel heard what happened and are determined to hold the evildoers responsible (Judges 20:1–10). Instead of cooperating, the tribe of Benjamin seems to resent this interference in their region. So, they rally their armies to oppose their countrymen (Judges 20:11–15).The other tribes sent a quantity of troops listed as 400 'eleph, described using a Hebrew word which can refer to "thousands" or to "units" or "divisions." The tribe of Benjamin has 26 'eleph, plus seven hundred more who are probably militia from Gibeah. The scenario is incredibly lopsided.
However, among this army are seven hundred men—a separate group from those in Gibeah—who have a special skill. These men fight with slings rather than swords. In that era, slings were not the "slingshots" modern people associate with children and recreation. These weapons were long strips of cloth or leather, cracked like whips, launching eyeball-sized stones at incredible speeds (1 Samuel 17:49). Some ancient slings used rocks as large as a person's fist, thrown faster than a professional baseball pitcher.
These Benjaminites are extremely proficient with these weapons. Commentators suggest the term translated as "left-handed" might mean the men were ambidextrous: trained to use slings with both the right and left hand. That skill seems to have been a hallmark of Benjamin's warriors (Judges 3:15; 1 Chronicles 12:2). In any case, their accuracy is described using a figure of speech, poetically saying they could fire stones with almost perfect accuracy. They will help to even to the odds stacked against Benjamin's smaller army.