Mishnah Berurah — משנה ברורה

One should wash his hands etc. - There are 2 reasons for this: The Ro"sh wrote that a person's hands are constantly in use and it's impossible that one did not touch "unclean" parts of his body (ie. parts of the body that require washing of the hands if they were touched) in the middle of the night [while sleeping] - therefore, the sages enacted that a blessing be said on this washing for [the sake of reciting] Shema and prayers [afterwards]; The Rashb"a wrote that since in the morning, after sleeping, we are like a new creation, as the verse states "Each morning refreshed, Your faithfulness is immense." (Lamentation 3:23), [therefore] we must give thanks to Him, Blessed Be He, that He created us for His honor to serve Him and to bless His Name - and regarding that, the sages enacted to recite all the morning blessings that we say each morning; therefore, also regarding this (ie. washing one's hands in the morning), the sages enacted for the morning to sanctify ourselves with His sanctity and to wash our hands from a vessel, like a Kohen who sanctifies his hands from the basin before his service [in the Temple]. And regarding how to conduct ourselves with washing our hands, we act stringently utilizing both opinions, as will be seen later in this siman. If one did not recite the blessing of על נטילת ידים before praying, he should not recite it after praying - [this is] according to all opinions. [Chayei Adam].