Reference for Chullin 185:3

חלב שהבשר חופה אותו מותר

and not of that which is in the loins; likewise here, the Divine Law spoke of that which is 'above the kidneys'<span class="x" onmousemove="('comment',' In connection with sacrifices, e.g., Lev. III, 4. The prohibition of fat applies only to such fat as was burnt in a sacrifice on the altar.');">¹</span>

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