In the morning one recites two blessings before [the Shema] and one after it, and in the evening [one recites] two [blessings] before [the Shema] and two after it; one lengthy [blessing] and one brief [one]. Where they said to recite a lengthy [blessing], one may not shorten [it]; [where they said] to recite a brief [blessing], one may not lengthen [it]. [Where they said] to con-clude [a blessing] with a closing formula, one may not conclude [the blessing] without the closing formula; and [where they said] not to conclude [a blessing] with a closing formula, one may not conclude [the blessing] with a closing formula.