2 Samuel 18:5-7

18:5 The king gave this order to Joab, Abishai, and Ittai: “For my sake deal gently with the young man Absalom.” Now the entire army was listening when the king gave all the leaders this order concerning Absalom.

18:6 Then the army marched out to the field to fight against Israel. The battle took place in the forest of Ephraim. 18:7 The army of Israel was defeated there by David’s men.¹ The slaughter there was great that day – 20,000 soldiers were killed.