Reference for Pesachim 94:1

ושביעית ביום טוב כהן ונזיר אבית הטומאה ואי אמרינן הואיל אחרישה לא ליחייב הואיל וחזי לכיסוי דם ציפור

and it is the seventh year, on a Festival, [and he is] a priest and a nazirite, [while this furrow is] in unclea ground.<span class="x" onmousemove="('comment',' V. Mak., Sonc. ed. p. 149, n. 1-9.');">¹</span> Now if we say 'since', let him not be liable for ploughing [on the Festival], since it is fit for cov the blood of a bird?<span class="x" onmousemove="('comment',' When a bird is slaughtered its blood must be covered, v. Lev. XVII, 13. This ploughing crushes the earth and makes it fit for that purpose, and since a bird might be slaughtered on the Festival, that too would be necessary.');">²</span>

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