The hand Tefillin are put on the "weak" hand, that is, the weaker hand of the individual wearing the Tefillin. The halakhic source for this is to be found in the verse in the passage "If, then, you obey ..." that states: "And so it shall be as a sign upon your hand and as a symbol on your forehead" (Exodus 13:16). In this verse, the word ("your hand") is written in the Torah with an additional letter heh at the end. The Rabbis learned from this that the Tefillin are to be placed on one`s weak ( (ëää hand. For most people, their left hand is the weaker one. A left-handed person, in contrast, who performs most actions with his left hand, and, particularly, writes with this hand, puts his Tefillin on his "weaker" (right) hand.