A little boy had a toothache and knew that, if he went to his mother, she would give him something to deaden the pain and let him get to sleep that night. But he did not go to his mother, at least not until the pain was very bad, because he knew she would also do something else – take him to the dentist the next morning.
He could not get what he wanted – immediate relief from pain – without getting something more – having his tooth repaired. And, since he knew dentists, he knew that something else would probably happen to his mouth, because dentists tend to fiddle about with other teeth, those that have not yet begun to ache.
Our Lord is like a dentist. People go to him to be cured of some particular sin. Well, he will cure us of that sin, all right, but he will not stop there. That may be all you asked for, but if you call him in, he is likely to give you the full treatment.