Strength

At a gathering where Mullah Nasruddin was present, people were discussing the merits of youth and old age. They had all agreed that, a man's strength decreases as years go by. Mullah Nasruddin dissented.
- I don't agree with you gentlemen, he said. In my old age I have the same strength as I had in the prime of my youth.
- How do you mean, Mullah Nasruddin? asked somebody. Explain yourself.
- In my courtyard, explained Mullah Nasruddin, there is a massive stone. In my youth I used to try and lift it. I never succeeded. Neither can I lift it now.