His sin is light and momentary, a spur of the moment kind of thing. He said to himself, "I'm here, candy's there, I like candy, no one's looking, boom. It's done, over with, gone." When is mother catches him, she gives him a spank, takes him back to the store, makes him apologize to the owner, and pays him back. The whole event causes the boy to change his mind about stealing and he never does it again.
There are other kinds of sin that are way beyond that kind of sin. If his mother had not handled the stealing the way she did, he might evolve into stealing larger and larger things. Eventually, his whole life would revolve around being a thief. His friends would be thieves, his home would be decorated in things thieves decorate with. His reading would reflect his lifestyle. His lifestyle would reflect his love for thievery. He would constantly think about things related to robbery and stealing.
Over time, someone on the outside looking at his life from far away, could see the transitions from stealing candy at the store to mugging little old ladies to robbing banks or rich people's houses. Sin, not dealt with, always develops and grows. It always gets boring, and needs to expand. It needs to flex its muscles and show just how wonderful it can be. Stealing candy is a thrill, but nothing like sneaking into a home where people are sleeping. But the man doesn't ever think of himself any differently than he did as a young boy. He's just in it for the thrill. He doesn’t think of himself as a thief. He’s just a guy who likes to live on the edge.
Suppose one day something happens that makes him take a serious look at what he’s been doing. Suppose for the first time he sees that his life is totally immersed in stealing in all its component parts. He can go one of two ways. He can either continue on and embrace the lifestyle all the more, justifying it by saying it isn't my fault, God made me this way, or my parents didn't discipline me, or I'm just like my old man. Or he can turn from his sin to Christ and let God cleanse him from the inside out.
In turning from his sin, he needs to realize that the sin controlled every aspect of his life. He will have to make some pretty serious decisions about who he is and who he wants to be in Christ. He will more than likely have to get new friends, change his living arrangements, get a new job, change where he goes and what he does for fun, and get new hobbies. In short, his life will have to undergo a complete makeover. In fact, he will need to be reborn. Jesus is Lord of all or he isn't Lord at all. When a person breaks one part of the law he breaks the whole law.
Also, because the sin encompasses his whole life, his changes need to be violent in nature. He must learn in a hurry that the life he has been leading is not his friend. It hasn't been doing him any good. In fact, it has been killing him. He needs to violently throw off the old life, every bit of it, and just as violently grasp on to Christ and his new life.
Another aspect to repentance is that of confession of sin and restitution. If the man has stolen from anyone, he needs to confess is crime/sin and do whatever he can to make it right. If he has involved others in his sin, he needs to confess his sin and ask for their forgiveness. Whole life sins always involve more than the simple sin itself. Because it is a life, there are always other sins related to it that need to be dealt with and confessed. If, in order to go out and steal stuff the man had to create alibis, which were actually lies. He will need to correct that. If because he was hanging out with a particular crowd when he as a thief and this crowd got rowdy on the weekends, he may need to do some confessing and restitution in that area of his life as well.
I know this is short. If you have any questions, please feel free to ask.