A young Lubavitch yeshivah student quickened his step down one of Manhattan’s busy boulevards. It was Friday afternoon, and he still had some more rounds to make. He was on his way to one of his ‘regulars’ a businessman whom he visited every Friday, sharing the messages of the Rebbe’s mitzvah campaigns.

As he entered the store, he noticed a marked change in the interior.

“Don’t ask!” the businessman greeted him with a strained look on his face. “My place has been flooded. I lost a great deal of merchandise. I’ve written a letter to the Rebbe requesting a blessing for a successful turn of fortune. Would you please deliver it for me?”

The yeshivah student assured the businessman that he would do so. As soon as an answer came, he hurried to notify his friend in Manhattan. “The Rebbe has instructed you to be meticulous in keeping Shabbos and Yom-Tov (festivals)” he told him.

The businessman was visibly agitated. “What does that mean?” he retorted indignantly. “I do observe Shabbos and the holidays.”

The student decided to inform the Rebbe of the man’s response. The Rebbe answered tersely: “The onset of Shabbos and Yom-Tov.”

That Friday, the student brought news of the Rebbe’s second answer to the businessman. Trying to help him put the Rebbe’s directive into practice, he inquired about the man’s routine on Friday nights.

“Well, obviously, I say Kiddush and sit down to a Shabbos meal.”

Suddenly, a thought came to the student’s mind. “When do you close your business on Fridays?” he asked.

“Oh, about seven or eight,” the man replied naively. During the ensuing conversation, the businessman learned for the first time about the correct time for the onset of Shabbos and holidays.