Judges 20:32

‘ And the children of Benjamin said, “They are smitten down before us, as at first.” '

This was their view of the position. They were overconfident and became careless, forgetting that their previous victories had been due to the slingers and the massed ranks of their enemies coming towards them.

Judges 20:32 b

‘But the children of Israel said, “Let us flee, and draw them from the city into the highways.” '

This was the strategy of the children of Israel, to draw the Benjaminites away from the city by pretending to be afraid of them and not able to face them. So they fled along the highways which enabled them to move at speed without becoming too disorganised, followed by the hotly pursuing Benjaminites.