Reference for Arakhin 7:3

הכל חייבים במקרא מגילה כהנים לוים וישראלים

is that not self-evident? - No, necessary [to state that] concerning the interruption of their [Temple] service, in accord with Rab Judah in the name of Rab; for Rab Judah in the name of Rab said: Both the priests in their [Temple] service, the Levites on their platform, the Israelites at their posts<span class="x" onmousemove="('comment',' V. Meg. 3b.');">²</span>

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