Judges 20:25

‘ And Benjamin went out against them from Gibeah the second day, and destroyed down to the ground of the children of Israel again eighteen eleph men, all these drew the sword.'

How many units went forward we are not told, but eighteen of them were again thoroughly defeated. It is very probable that again it was largely due to the slingers. The children of Israel were swordsmen and could not cope with this weapon that knocked them down to the ground before they had even reached the enemy.

The eighteen eleph felled here, together with the previous twenty two eleph of the first battle, may make up the forty eleph mentioned by Deborah in her song (Judges 5:8). If so the choosing of ‘new gods', as Dan had done, may well be part of the reason for their two defeats. But they had also still not committed their full forces against their enemy.

Again we are not to think of forty units all killed. The wording is declaring that they were thoroughly defeated, not that all were killed.