In Jewish tradition, kissing holy things is a common act that pious Jews engage in several times every day. In his book, To Pray as a Jew, Rabbi Hayim Halevy Donin writes:
“Kissing is a universal sign of affection. It is an act of love, an expression of endearment, not only between man and woman, parents and children, but is also the expression of one’s feelings for the ritual objects and the religious duties associated with them.
There are no religious laws that require us to kiss a ritual or holy object. There is only the force of custom as it develops through the ages. In varying degrees kissing has become an optional commonplace among the Jews as an expression of religious devotion at the following times:
- The tallit [prayer shawl] is kissed just before putting it on.
- The tefillin [phylacteries] are kissed when taken them out of their bag and before replacing them in the bag.
- The mezuzah on the doorpost is sometimes kissed upon entering or leaving a house. It is done by touching the mezuzah with one’s hand and kissing the fingers that made contact with the mezuzah.
- The Torah is kissed when it passes by in the synagogue. Here, too, it is often done by extending a hand to touch the Torah mantle and then kissing the hand. Some touch the Torah with the edge of a tallit and then kiss the tallit.
- The Torah is also kissed before one recites the blessings over it. Here it is done by taking the edge of one’s tallit or the sash that is used to tie the scroll together, touching the outside of the scroll with it, and then kissing the tallit or the sash. Many people place the tallit or sash to the very words where the reading is about to begin. The sages advised against doing this as it may hasten a wearing away or erasure of the letters. At best, they recommend touching only the margin area near the line where the reading is about to begin. In all instances, one should not touch the Torah parchment with one’s bare hand. The custom of not doing so derives from a special edict issued by the sages prohibiting such contact (Shabbat 14a: OH 147:1).
- The curtain on the Ark (parochet) is kissed before one opens it, or after closing it when the Torah is put away.
- A siddur [prayer book] and Chumash [Jewish Bible] are kissed before putting them away. These holy books are also kissed if they are accidentally dropped on the floor”
(From To Pray as a Jew: A Guide to the Prayer book and the Synagogue Service, pg. 43f).