or for a star or any other heavenly body—on what basis, then, is it forbidden?

The answer has already been pointed out: Allah, exalted is He, has forbidden whatever is slaughtered upon the altars (anṣāb). That alone makes it unlawful even when the slaughterer is a Person of the Scripture; for, had the ban rested merely on the slaughterer’s being an idol-worshipper, there would be no difference between sacrificing on an altar and elsewhere. Moreover, since Allah has declared the food of the People of the Book lawful for us, it follows that the food of the polytheists is unlawful; thus, His singling out what is slaughtered for an idol conveys an additional ruling.

He has also mentioned in the same verse the prohibition of that which is slaughtered on the altars and of that ‘over which a name other than Allah’s has been invoked.’ Whatever the People of the Book offer to anyone besides Allah falls under this latter heading, and the same applies to everything sacrificed on an altar. Therefore, if a Scripturalist slaughters an animal upon one of the statues erected in their churches, it is deemed slaughtered on an altar. Clearly, the ruling is the same whether the idol is physically present or absent, for the prohibition stems from the intention to worship and venerate the idol through the act of slaughter.

As for these anṣāb, some scholars say they are themselves idols, while others maintain that they are distinct from idols. It is related that around the Kaʿbah there once stood three hundred and sixty stones upon which the people of the pre-Islamic period would slaughter animals and carve up their meat; they revered and worshipped those stones, offering sacrifices upon them, and whenever they wished they would replace them with others they found more pleasing.

This is corroborated by the words of Abū Dharr, may Allah be pleased with him, in the account of his embracing Islam: ‘until I became like the red altar,’ meaning that it would turn red from being soaked in blood.