One morning, which happened to be a fast day on the Jewish calendar. The porter roused his son at the usual time, and off to the synagogue they went. When they had finished praying, the porter informed his son that today there would be no eating due to the fast.
The day wore on. The son grew hungrier and hungrier. He kept asking his father continuously when they would finally be able to eat. Finally, the day ended and his hunger was satisfied.
The following morning, the boy refused to budge when his father tried to wake him. With an air of indignation the boy told his father, “I do not want to get up, and I do not want to work. I am afraid that you will not let me eat anything today either!”
“Ah, my son, have no fear,” replied the porter. “Today is not yesterday.”
Whenever the Rashbatz, the great chassidic mentor, told this story, he would tap his listener on the shoulder, as if to exclaim, “Get up! Today is not yesterday!”