“…for me the earth has been made a place of prostration and a means of purification.”
They maintained that this report abrogates all the others, for it counts among the special merits granted to the Prophet—peace and blessings be upon him—and such distinctions, they argued, are not subject to abrogation.

Those who adopted the method of construing the specific text as a limitation upon the general said: “The ḥadith that grants permission is general, whereas the ḥadith that forbids is specific; the specific must therefore be applied as an exception to the general.”
Within this camp, some excepted all seven locations; others excepted only the bathhouse and the graveyard, asserting that these two prohibitions are independently established; yet others excepted only the graveyard in light of the previously cited report.

A third group sought reconciliation without carving out any exceptions from the general wording.
They held that the reports of prohibition indicate mere disapproval (makrūh), while the original report affirms permissibility.

The jurists also differed about praying in synagogues and churches.
Some disapproved, others allowed it, and a third opinion distinguished between buildings that contain images and those that do not.
This latter view is attributed to Ibn ʿAbbās, based on ʿUmar’s statement: “We will not enter their churches because of the statues.” Those who rejected prayer there did so—not on account of the images—but out of concern for ritual impurity.

They all agreed that praying directly on the bare ground is permissible, but they disagreed over praying on carpets and other floor coverings.
The majority permit prostration on reed mats and similar items that grow from the earth, and regard anything beyond that as disliked; this is also the position of Mālik ibn Anas.

[Chapter Seven: Concerning the Omissions That Are Conditions for the Validity of Prayer]

Chapter Seven deals with the conditions—namely the things that must be left—in order for prayer to be valid.
Muslims concur that some of these conditions pertain to speech and others to actions.

As for actions, every permissible movement that is not one of the prescribed acts of prayer must be left, with the exception of killing a scorpion or snake during the prayer. On this latter point they disagreed, because the textual evidence appears to conflict with analogy, although—so far as I know—they all allow a slight movement.

As for speech, it is likewise every utterance that does not belong to the formulas of prayer. Here, too, they have unanimously agreed that deliberate speech invalidates the prayer, in light of the Almighty’s words:
“Stand before Allah in devout obedience” (Q 2:238),
and the Prophet’s statement—peace and blessings be upon him:
“Allah decrees in His affairs whatever He wills, and among what He has newly decreed is that you must no longer speak during the prayer.”