Charles Ellicott Commentary 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." — 2 Samuel 14:30 (ASV)

Set it on fire. —Absalom’s stratagem for obtaining an interview with Joab was perfectly successful, but would only have been resorted to by a lawless and unscrupulous character.