How long do you wait for a rabbi?

I was late to Torah study last week (undoubtedly some combination of children, chickens, and exhaustion). The three hardy and dedicated souls who had come to learn with me stood on the corner discussing the question: “If you wait 20 minutes for a full professor, 15 minutes for an associate professor, 10 minutes for an assistant professor, and 5 minutes for a lecturer, how long do you wait for a rabbi?” Then I showed up, and one consulted her watch. “I guess the answer is 17 minutes!”

To which I replied, “Well if we’re at 17 minutes now, then the answer is obviously 18, and I slipped in under the wire!”

“Oh, of course — 18!”

What you have to know is that every Hebrew letter has a numeric value. The word for “life” is chai

Word Chai in Hebrew

(actually chai means “living,” click here to get the details) and the two letters that make up the word chai have the numerical value of

10 (yud) white Yud with yellow patterned background and 8 (chet) white chet with blue patterned background. So eighteen is a special number for Jews. We often give gifts or tsedakah (donations of money) in multiples of 18. I’m sure that the various charities I support can’t figure out why they get $36 instead of the requested $35, or why they get $72 instead of $75. It has significance, that’s why: it reminds me that I am doing tsedakah, justice, sharing the wealth because it is the right thing to do, not just doing it out of the goodness of my heart. It reminds me that I am doing a mitzvah — fulfilling an obligation.

So nu: How long should my Siena College students wait, when I’m teaching the Judaism course in the Spring as a lecturer rather than as a rabbi???