Plant a Tree

A wise man was walking along a road when he saw a man planting a tree.
The wise man asked him “How many years will it take for this tree to bear fruit ?”
The man answered that it would take seventy years.
The wise man asked “Are you so fit and strong that you expect to live that long and eat it’s fruit?”
The man answered, “I found a fruitful world because my forefathers planted for me. So I will do the same for my children.”