<p class="MsoNormal" style="margin: 0cm 0cm 10pt;"><span style="mso-ansi-language: EN-US;" lang="EN-US"><span style="font-size: small;"><span style="font-family: Times New Roman;">Over forty years ago, I went to visit a friend and when I reached his front door, I kissed the mezuzah, The mezuzah case had a metal letter &ldquo;shin&rdquo; on it and the points at the top of this letter were sharp. As a result when I kissed the mezuzah I cut my hand! I mentioned this to the master of the house (who incidentally today is the Rabbi of an Israeli town and a Rosh Yeshivah). He answered me that the protection afforded by a mezuzah is only when you are already inside the house but you were still outside when this happened! [see Bavli Avodah Zarah 11a and Yerushalmi Peah chapter 1 halachah1]</span></span></span></p>