Prescott has been watching them for at least a couple of days and checking out the farm, his own words tell us that.
“Yep, it’s me what got you boys trapped like rats in a half-filled trough, and I’m here to settle a few scores, make no mistake. That one you shaved earlier still alive? The dumb farmer who thinks he be smarter than me?” He chortled after, and it set Jubal’s teeth on edge.
He and Lucas shared another look. How long had they been watched? “You were going to rob us on that road!”
“If’n you come out from yonder and show me where my gold be, I just might let you live. Just the one of you, though. I know them coins ain’t where you been sleeping, and they ain’t where you are now, and not the barn neither, so don’t be lying to me.”
“He’s been through the buildings,” Lucas said, his pale face full of anger. “He ain’t planning on letting either of us live… can hear it in his voice.”
Prescott has already checked the cabin, most likely during the day while Jubal and Lucas have been working on the farm. So he also knows they don't have any guns on them, but Jubal has him thinking as he doesn't know if Jubal does or doesn't have any knives on him.