Devarim 11:18-20

Therefore shall ye lay up these My devarim in your lev and in your nefesh, and bind them for an ot upon your hand, that they may be as totafos (ornaments, Ex 13:16, Shabbos 57a) between your eyes. And ye shall teach them your banim, speaking of them when thou sittest in thine bais, and when thou walkest by the way, when thou liest down, and when thou risest up. And thou shalt write them upon the mezuzot of thine bais, and upon thy she'arim