(this story comes from the Talmud and is retold by Michele Mindek)
There once was a man named Honi. He was walking along one day and saw a man planting a carob tree. Honi asked the man, "How long will it take for that tree to grow?"
The man replied, "Seventy years."
Honi looked shocked as he asked, "How do you know that you will live another seventy years?"
"I don't, but just as my grandparents and parents planted for me, I am planting this tree for the generations to come," replied the man.
"Well fine," said Honi, as he left. After walking for about an hour, Honi realized he was exhausted. He lay down on the dusty ground right next to a large rock. When he awoke, he was so shocked he had to pinch himself to make sure he was not dreaming. The dusty ground had become a large grassy field, and the rock was gone. In its place was a huge carob tree, towering over a glittering pool of blue water.
Honi walked back the way he had come, but he did not realize this was the way he had come. All of a sudden, he recognized his surroundings as the very place he had come from 70 years before. In the place where he had watched a man planting a carob sapling stood a towering carob tree. Honi realized then that he had been asleep for 70 years.
When Honi returned to town, nobody recognized him. He told everyone who he was and they didn't believe him, but they were kind to the wise, old stranger.
Honi lived a full life, in which he choose to travel the Land of Israel planting carob trees for future generations.