I believe in doing the right thing because it's the right thing to do, not for some childish reward/threat.
Say there are two boys, Billy and Bobby. When their mother tells them to go clean their rooms, Billy says "ok mom, it's my room and I got it dirty so I'll go clean it".
Bobby, on the other hand tells his mom, "No. Not unless you give me something". So mom says, "I'll make your favorite dinner tonight if you go clean your room (heaven). Of coarse, if you don't clean you room, I'm going to spank your butt (hell). So Bobby goes to clean his room.
So both boys cleaned up their rooms, but for different reasons. Which kid would you say cleaned his room for the right reason? Gymbob