How can one scientifically refute those who say that carrying something of the Qur’an in one’s heart does not prevent entering restrooms, using this to indicate that Allah is not too exalted for impure places, and should one tell them that the words in people's hearts are created?

The belief that Allah is everywhere necessitates His presence in vile places. Citing the presence of the Quran in the Muslim's heart and their entry into the lavatory is incorrect, because the ruling applies to the Muslim's body, not to an attribute of Allah. Allah's presence in the believer's heart means His love and knowledge, not that Allah's essence has resided therein. Allah's word in the believer's heart does not mean that the Lord's attribute has resided therein.

Ibn Taymiyyah said: The saying "The heart is the house of the Lord" and what was narrated in the Isra'iliyyat (Judeo-Christian traditions) "My earth and My heavens did not encompass Me, but the heart of My believing servant encompassed Me" means that the heart encompassed faith in Allah, His love, and His knowledge, and not the indwelling of Allah's essence therein. And whoever says that Allah's essence indwells in people's hearts is more infidel than the Christians.

There is a difference between the existence of essences and attributes; attributes do not subsist by themselves but by essences. Allah's knowledge is an attribute that does not subsist by itself but by His essence. And if Allah grants a servant something of His knowledge, it does not mean that Allah's attribute has resided in them.

Muslims do not say that the Quran is a self-subsisting essence, rather it is Allah's speech with which He spoke, and they do not say that it united with humans.

As for the indwelling of the Quran in copies (mus'hafs) and breasts, there is a disagreement among scholars regarding it. Allah's speech does not part from Allah's essence, nor does it diverge from it, nor do His attributes transfer to others.

Imam Ahmad said: "Allah's speech, from Allah, is not separate from Him," and "that it began from Him, and from Him it emerged," meaning that He is the One who spoke it.

The speech of a created being does not diverge from its locus. What is in the scroll corresponds to its wording, and its wording corresponds to its meaning, and its meaning corresponds to the external reality.

A Muslim who memorizes the Quran may enter the lavatory, but it is not permissible for them to recite the Quran there.