In its initial form, nefilas apayim consisted of lying on the floor before Hashem. Since the Torah prohibits prostrating oneself face-down on a stone floor, it was necessary to tilt one’s head and body to the side. Even after our way of saying Tachanun changed, the custom of turning one’s head to the side remains (Biur Halacha 128,1).

Which direction we should turn on depends on how we are positioned in relation to the Shechina. The verse, “Hashem is your shadow on your right side” (Tehillim 121,5), implies that the Divine Presence is on one’s right. Based on this verse, some opinions rule that a person should rest his head on his left arm, and turn his face to the right, so that he will be facing the Shechina (Shulchan Aruch 131,1).

On the other hand, the verse, “I place Hashem before me always” (Tehillim 16,8), implies that the Divine Presence is directly in front of a person. Some authorities maintain that when leaning on one’s right arm and turning one’s head to the left, a person faces the right of the Shechina, which is before him (Tur 131,1). When one’s head is turned away from the left side of the Shechina and faces the right side instead, he fulfills the verse, “His left side is behind my head and His right side embraces me” (Shir Hashirim 2,6).

The Rema offers a compromise between these two options (128,1). In the morning, while wearing tefillin on one’s left arm, in order not to rest one’s head on the tefillin a person should lean on his right arm and face left. During Mincha, when one does not wear tefillin (according to most opinions), he should lean on his left arm and face right.

Text Copyright © 2010 by Rabbi Daniel Travis and Torah.org