he let them go
Exodus 22:6
If fire break out, and catch in thorns, so that the stacks of corn, or the standing corn, or the field, be consumed therewith; he that kindled the fire shall surely make restitution.
2 Samuel 14:30
Therefore he said unto his servants, See, Joab's field is near mine, and he hath barley there; go and set it on fire. And Absalom's servants set the field on fire.