Not necessarily a Buddha teaching. But, one I could see him saying.
"24 Hours To Die
Raj asked Buddha, “Reverend Sir, how come my mind wanders around to forbidden places and yours does not?” “Sir, how come I do back-biting and you don't?” “Sir, how come I don't have compassion for others, while you have?” All the questions that Raj asked were of similar nature.
Buddha replied, “Raj, your questions are good, but it seems to me that in 24 hours from now you will die.”
Raj got up and started getting ready to go.
Buddha asked, “Raj, what happened? You came with such vitality now you are totally dismayed.”
Raj said, “Sir, my mother told me that your words are true and are to be held in high esteem. So please let me go so that I may meet my family members, friends and others before I die.”
Buddha said, “But there are still 24 hours. Sit, we will talk more.”
Raj said, “Reverend Sir, please let me go. I must meet my people before I die.”
So Raj left and went home. Met his mother and started crying. The word spread. His friends came; other family members came; neighbors came. Everyone was crying with Raj. Time flew.
Raj was busy either crying or counting the hours. When only 3 hours were left, he pulled up a cot and lay down. Although the Death had not yet arrived, poor Raj was kind of dead.
When only an hour was left, Buddha walked in.
Buddha said to Raj, “Raj, why are you lying down on the cot with your closed eyes. Death is still an hour away. And an hour is 60 minutes long. That's a lot of time. Get up, let us talk.”
Raj: “Sir, what is it now that you want to talk? Just let me die peacefully.”
Buddha: “Raj, there is still time and our talk will get over before the 'ordained' time.”
Raj: “Okay, Sir . . . say what you have to say.”
Buddha: “In the past 24 hours, did you curse anyone?”
Raj: “How could I curse anyone? I was all the time thinking about death.”
Buddha: “In the past 24 hours, did you think or wish ill for anyone?”
Raj: “How could I do that? I was all the time thinking about death.”
Buddha: “In the past 24 hours, did you steal?”
Raj: “Sir, how can you even ask that? I was all the time thinking about death.”
Finally the Buddha said, “Raj, I don't know who has to die and who has to live. But understanding the ultimate truth — i.e. death — can be very enlightening. All the questions you posed to me have been answered by yourself because of the awareness of death that you experienced during the past 24 hours. The difference between me and you is that you were aware of death for the past 24 hours, I have been aware for the past 24 years.” "
- Source: www.gakkaionline.net/Myths/24Hours.html
