"You're going to need a bell or a horn," said the store attendant. "And, of course, a helmet is a must - you know it's the law here in Canada."

David knew. His friends always wore kid-sized helmets when they rode their bikes. He tried on a few until he found a bright yellow one that fit perfectly. The attendant held up a mirror for his young customer. "Now I'll never get hurt riding my bike," David announced confidently, looking at himself.

On the way home, David's father explained, "No one can be one hundred percent sure that they won't get hurt when they are wearing a helmet. A helmet isn't an automatic guarantee for safety. It's HaShem, not the helmet, that protects us. Someone riding a bike can fall and hurt himself whether he wears a helmet or not. When he wears a helmet, though, he may not be hurt as badly as he would have been otherwise.

"David, can you think of a mitzvah in this week's parshah that reminds us of your helmet?"

"A helmet in the parshah?!" David asked in surprise.

"I don't mean an actual helmet, but a mitzvah that works like one. I'll give you a hint - you say it every day in the Shema."

"Oh, I know! I know! It's the mezuzah."

"That's right," said his father. "In this week's parshah, Eikev, we read 'Vihayah im shamoa,' the second portion of the Shema, which tells us, "And you shall write them for a sign on your gates." Pessukim from this portion are written in the mezuzah. Do you remember what is written on the outside of the mezuzah?"

"Yes," answered David. "They're the letters Shin, Dalet, and Yud."

"Right. Those letters stand for Shomer Dalsos Yisrael - "He guards the doors of the people of Israel," his father told him.

"That's neat!" exclaimed David. "Like a secret security code."

The mezuzah is top notch security that comes all the way from the top," smiled his father. "There are many stories that show how mezuzos are closely connected with a Jew's safety and well-being. As with a helmet, we can't be sure that a mezuzah will save a person every time he may be in danger. But we do know that HaShem uses the mezuzah as one of His ways to 'package' His protection.

"By the way, that reminds me - the month of Elul is just around the corner. It's the month when we should check our mezuzahs and make sure they are kosher."