Ben is not a savory-looking character. He is fat and slovenly-looking, "heavyset, the fat bulging under a ragged blue army coat...his face...almost invisible behind a tangle of reddish whiskers...(with) small blue eyes that glittered." Although appearances do not tell everything, Matt is not reassured by the man's unkempt look.
Ben is also very forward in his behavior. As soon as he arrives at the door, he "peer(s) curiously over Matt's shoulder through the open door...he could easily see that the cabin was empty." The fact that Ben immediately discerns this is verified when he asks Matt, "You all alone here?" Ben's imposing manner also shows itself when he eyes the rifle hanging over the door, letting out "a slow, admiring whistle" and going over to touch it, running his hand over the stock. He comments that the rifle is a "mighty fine piece...worth a passel of beaver." Ben does not hide the fact that he covets Matt's father's rifle. Ben's tendency to manipulate the situation and take full advantage of Matt's inclination to be hospitable is again evidenced in the way he asks for a meal, eats it greedily, asks for tobacco, then falls asleep on the floor. The man is clearly a taker, and he is out to get whatever he can for himself.
Another reason why Matt is uneasy about Ben is because of something the older man says in telling about himself. He says that he had left town in a hurry, implying that he had gotten himself in trouble with the law. Ben just does not seem like an upright character, and though he might like to, Matt has a hard time trusting him (Chapter 3).