It is important for men to recite the Shema of Shaĥarit while wearing tefillin, which contain the first two paragraphs of the Shema. (Nevertheless, even a man who does not have access to tefillin is obligated to recite the Shema, since these are two independent mitzvot.) Additionally, for those who wear a tallit gadol (20:11 above), it is preferable to wear it while reciting the Shema, since the third paragraph of the Shema is the source of this mitzva. For these reasons, the custom is to wear both the tallit and the tefillin during Shaĥarit. One first puts on his tallit and afterwards his tefillin. This is because tefillin have more sanctity than a tallit, and the general preference is to ascend in levels of holiness.
