What can inhibit even an unbeliever from acting on the old Adam?

Les explains that he thought about his own service days in basic training, where he was a couple of years older than most of the 17-year-olds. They would do things they never did in their hometown. When he asked why, they said, "Because nobody knows me." Les uses this as the perfect answer: even an unbeliever can be inhibited by his surroundings, circumstances, parental influence, and community influence. But in a totally strange environment away from home where no one knows them, the old Adam has free course. This same dynamic explains how soldiers of an invading army can pillage a community and rape women without seemingly being bothered. Les says that is the old Adam, and every one of us, before we were saved, would have been capable of those same things. Paul is showing that the old Adam abounds with sin, but where sin abounds, the grace of God is always greater. In verse 21, sin—the old Adam—has reigned like a king, but grace can also reign like a king, presenting two alternatives.