“Prayer is neither valid inside a cemetery nor toward it, and the prohibition serves to block the avenues that lead to shirk (polytheism). Some of our colleagues have defined a cemetery as any place containing three graves or more. Nothing in the statements of Ahmad or the majority of his disciples, however, supports such a distinction; rather, the broad language they use—along with their reasoning and the proofs they cite—requires forbidding prayer at even a single grave, and that is the correct view. A ‘cemetery’ is any location in which someone has been buried; it is not merely the plural of ‘grave.’
Our scholars also say: everything that falls under the name ‘cemetery,’ including the surrounding area, is a place where prayer is not to be performed. This clarifies that the prohibition encompasses both the sanctity of an individual grave and the ground appended to it.
Al-Āmidī and others have stated that it is impermissible to pray in a mosque whose qiblah faces a cemetery unless there is another barrier between the mosque wall and the graveyard; some have maintained that this is the explicit ruling of Ahmad.”
They have differed over the reason for the prohibition against praying in cemeteries. Some said it is because of impurity; others said it is to avoid imitating the People of the Book and to block the means to shirk, as mentioned by Shaykh al-Islām and others. The latter view is what is evident from the collective body of hadiths on this subject—some of which have already been cited, while others will follow.
Upon this basis our later Ḥanafī scholars have proceeded. Ibn ʿĀbidīn says in his commentary:
“The rationale (i.e., for the reprehensibility) is disputed. Some said it is because the cemetery contains the bones and pus of the deceased, which are impure—but this is open to objection. (1) Others said that the origin of idol worship was the adoption of the graves of righteous people as places of prayer. Still others said it is because the practice resembles that of the Jews, and this is the position adopted in the marginal note.”