“We should be particular with regard to the mezuzah, which is a duty incumbent uninterruptedly on every one. Whenever we enter or leave the house our eye meets with the name of God; we remember His love, and rousing ourselves from our torpitude, we are led to regret our foolish devotion to the vanities of the time, and recognise that nothing remains for ever except the knowledge of the Rock of the universe. We shall then at once devote ourselves to know Him, and walk in the way of uprightness. Our ancient Sages said, ‘He who has tefillin upon his head and upon his arm, tsitsith on his garment, and mezuzah on his door, he is safe from sin, since he has many reminders of his duties, and these are the angels that protect him from going astray; and to him the following verse applies: “An angel of the Lord encampeth round those who fear Him”’” (ibid., Hilchoth mezuzah vi. 13). 2. The great importance of the tefillin, as described by Maimonides, was not understood or recognised by all Jews. Various sayings occurring in the Talmud indicate the existence of laxity or even opposition with regard to the carrying out of this precept in its literal sense. When persons with tefillin on their head and on their arm showed by their conduct that their heart was not filled with the holiness and uprightness of which the tefillin are the symbol, it was but natural that not only were these persons accused of hypocrisy, but the Divine precept itself was discredited. But the greater the opposition by one section of the Jewish community, the more the enthusiasm of the other section grew in its favour. Hence the numerous Talmudical and Rabbinical utterances concerning the sanctifying force inherent in the tefillin (comp. Tur Orach Chayyim xxxvii.). Thus, when a Rabbi was cautioned not to be over joyous, as excess of joy led to sin, he replied, “I lay tefillin;” i.e., “The thoughts which the observance of this precept awakens protects me from sin.” This idea of protection from sin may be the origin of the Greek name phylacterion, “protection.”—In times of persecution, when the Jews were forbidden by their oppressors to perform any of their religious rites on penalty of death, the precept of tefillin was not included among those which they performed even at the risk of their life. To this circumstance Rabbi Simeon b. Elazar ascribes the laxity with regard to the tefillin (Babyl. Talm. Shabbath 130a).