Berakot 1:1

Questions concerning Berakot 1:1

From what time do they recite the Shema in the evening?

On what basis does the Tannaite authority stand when he begins by teaching the
rule, “From what time…,” [in the assumption that the religious duty to recite the
Shema has somewhere been established? In point of fact, it has not been
established that people have to recite the Shema at all.]
Furthermore, on what account does he teach the rule concerning the evening at
the beginning? Why not start with the morning?