Reference for Pesachim 24:7

אי הכי בשית נמי ניכול אמר רב אדא בר אהבה שית יומא בקרנתא קאי

And according to Raba who maintains on R'Judah's view [that] a man may err in three hours less a trifle, let us not eat from the beginning of the fourth [hour]? - In the fifth [hour] the sun is in the east, while in the seventh it is in the west, and all the more s the fourth. If so, let us also eat in the fifth [hour]? - Abaye answered this on Raba's view: Testimony is committed to men of care, [whereas] leaven is committed to all.<span class="x" onmousemove="('comment',' Hence in the matter of leaven people may err between the fifth and the seventh hours, in spite of the difference in the sun's position. Nevertheless, they would not err from the fourth to the seventh.');">⁹</span>

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