Guide for the Perplexed, by Moses Maimonides, Friedländer tr. [1904], at sacred-texts.com
THE precepts of the ninth class are those enumerated in the Section on Love. Their reason is obvious. The actions prescribed by them serve to remind us continually of God, and of our duty to fear and to love Him, to keep all His commandments, and to believe concerning God that which every religious person must believe. This class includes the laws of Prayer, Reading of Shema, Grace, and duties connected with these, Blessing of the priests, Tefillin, Mezuzah, Ẓiẓit, acquiring a scroll of the Law, and reading in it at certain times. The performance of all these precepts inculcates into our heart useful lessons. All this is clear, and a further explanation is superfluous, as being a mere repetition and nothing else.