The Babylonian Talmud begins its discussion of this Halacha by comparing two earlier sources:
The Tosefta’s “its” (Mitzvah) refers to the morning recitation of the Shema as mentioned in the previous unit. The Shema concludes with a reference to the redemption — the Exodus from Egypt. By reciting the Shema between dawn and sunrise, one is then able to recite the morning prayer afterwards at sunrise — adjoining redemption with prayer.
At first glance, the Tosefta appears to conflict with the Mishna. If the morning prayer should be recited at sunrise, how can the Mishna state that the time for the morning prayer extends until noon?
The Babylonian Talmud continues:
The resolution to our dilemma is that the Tosefta is describing the ideal practice for someone who rises early at dawn. Such a person completes the morning Shema by sunrise and immediately proceeds to recite the morning prayer afterwards. For those who do not rise so early, they can pray the morning prayer until noon.