Davening — praying — with tefillin involves binding leather boxes containing Torah passages to the arm and forehead each weekday morning, a practice taken directly from the literal reading of a commandment. The three daily services, the prayer shawl, and the direction faced are all specified. What strikes observers is the ordinariness of it: this is not an occasional devotion but a fixed structure the day is built around, performed alone if necessary and in a quorum of ten when possible.