Hil. Tefillin 4:26 "Even though the commandment of Tefillin applies the duration of daylight, it especially applies while praying. The Sages said, 'Whoever recites Shema while not wearing Tefillin is as though he gives false testimony about himself.'"
Hil. Mezuza 6:13 "The Sages said, 'Whoever has Tefillin on his head and arm, Sisith on his garment, and a Mezuza at his entrance, he can be assured that he will not transgress;' For he has many reminders. And these are the angels that rescue him from transgressing, as it states, 'The angel of HaShem encamps around those who fear Him, and he delivers them.' (Ps. 34:8)