"If someone starts a fire in his own field and it spreads through the weeds to someone else's field and burns up grain that is growing or that has been cut and stacked, the one who started the fire is to pay for the damage.

So Absalom said to his servants, "Look, Joab's field is next to mine, and it has barley growing in it. Go and set fire to it." So they went and set the field on fire.