If you have not trained the child to temperance by the time he is three or four years old, then you have allowed depravity to perfect itself . He won't unless you add some element that convinces him there is more immediate pleasure in principle than passion, or more immediate pain in passion than in principle. The child cannot yet understand that which is obvious to a mature Christian, that lack of self-control is sin, and in the end sin brings misery and death. There is a sowing and reaping principle in place. All intemperance, willfulness, lust, greed, self-seeking, and carnal indulgence is sin.
Sin ends in death.
The Bible testifies that in eternity sin will end in damnation. Parents must modify the child's environment to make the negative consequences immediately apparent to the child. Parents must construct circumstances so as to give the child a true representation of reality. You cannot tell a child that it is illegal to ride in a car unless in a restraining devise. He will not understand the cost of a ticket or the potential for harm, but he can well understand the harm to his backside if he does not immediately sit down, buckle up, and enjoy the ride.