What is the wisdom behind removing one's sandals when entering a cemetery?

The Shaykh : He says removing the shoes in the cemetery, knowing that it is not ... .

The questioner : Peace be upon you.

The Shaykh : And peace be upon you and the mercy of Allah. What does the questioner mean by this question?

The questioner : Is the questioner here?
Another questioner: Yes

The Shaykh : What do you mean?

The questioner : .. they are impure ... .

The Shaykh : The cemetery, I mean? What do you intend by the question, I mean? You say removing the shoes in the cemetery, knowing that it is impure; this statement is not complete. What is the predicate? I mean, for example, what is its ruling?

The questioner : Yes, yes

The Shaykh : So what do you mean by the reasoning, by the reasoning that it is impure?

The questioner : ... .

The Shaykh : Is the cemetery impure? The question is: is the cemetery impure or not?

The questioner : ... .

The Shaykh : Let the questioner himself clarify his statement.

The questioner : ... .

The Shaykh : This question?

The questioner : Yes

The Shaykh : And upon you be peace and Allah's mercy and blessings.
The answer is yes, and the issue has no relation to the cemetery being impure or not impure, because the ruling—namely, the ruling on removing the sandals of the one who wants to walk in the cemetery—did not come with a note that the cemetery is impure or pure, but rather with a note regarding the respect for the dead of the Muslims. It was reported in the Musnad of Imam Ahmad and elsewhere that the Prophet (peace and blessings be upon him) saw a man walking in the cemetery wearing his sandals, so he (peace and blessings be upon him) said: Whether a person walks in his sandals, in his leather socks, or barefoot, the cemetery is the cemetery, whether its ground is pure or impure. So this issue, namely whether the cemetery is impure or pure, has no relation to this ruling. All that is the case is that the prohibition of the Messenger (peace and blessings be upon him) for a Muslim to walk in his sandals in the cemeteries, the cemeteries of the Muslims, is like his prohibition of sitting on these graves, where it was reported in Sahih Muslim from the hadith of Abu Mufad al-Ghufari that he said: The Messenger of Allah (peace and blessings be upon him) said: because of the humiliation it entails, and do not pray facing them because of the sanctification and exaltation of them, an exaltation that goes beyond the limits of Islam. And this, and all of this, namely whether the prohibition of sitting on the grave or the prohibition of facing the grave in prayer, as well as walking between the graves in sandals, all these rulings have no relation to the purity or impurity of the cemetery, but rather they are independent rulings, completely separated from the consideration of whether the cemetery is impure or pure. It is not because it is impure, but because there is an exaltation of the grave more than what is necessary. It is not because it is impure, but because there is humiliation to it. Islam came with the middle path and commands the respect of the graves of the Muslims, but a respect that does not lead to exalting them with an exaltation that exceeds the limit of the Shari'ah. Likewise, the prohibition of walking in the cemetery in sandals has no relation to the cemetery being pure or impure. However, after this answer, we say that it is not permissible to rule that the ground of the cemetery is impure, because the ground of the cemetery is above the grave, and the grave and what comes out of it, namely pus and other disgusting or impure things, are below and not above. The surface of the grave, the cemetery, is exposed to the elements of nature, such as rain, wind, and sunlight, and all of these cause transformation, meaning they change the apparent state of what is exposed to these natural elements. From this, it is among the legal rulings in some Islamic schools of jurisprudence, such as the school of Abu Hanifa, that transformation is purifying. They mean by transformation the change of the reality of a thing to another reality. And that thing may originally be impure, so due to the transformation it becomes pure. For example, a carcass; due to its exposure to those elements—sun, wind, rain—it becomes salt. It is originally a dead, forbidden, impure carcass, and with the elements of nature, its reality changes and it becomes salt that you eat as you eat natural or industrial salt, so it becomes lawful and pure. This is transformation, or the change of a thing from one essence to another. If the essence was originally impure and then its reality changed and became another reality, then this other reality is looked at according to its current state, not according to what it was in its original state. This visible ground of the cemetery has no apparent impurity. The impurity may be below. Therefore, what is said that the reason for the prohibition of praying in the cemetery is impurity, this statement is not correct legally. The reason for the prohibition of praying in the cemetery is like the reason for praying facing the grave itself. The grave is far from you and you are praying facing it, so this is forbidden and the prayer is not valid, not because what you are facing is impure, no, but because you are exalting other than Allah (Mighty and Majestic) with your prayer. Likewise, the prohibition of praying in the cemetery is not because the cemetery is impure, but because in that there is imitation of the worshippers of graves.
In summary, it is established that the Messenger (peace and blessings be upon him) ordered the one who was walking in his sandals in the cemetery to remove them, so we took from that that among the etiquettes that Muslims must observe, with due regard, is that they do not walk in their sandals in the cemeteries of the Muslims. This is part of the etiquette of Muslims with their dead after their burial.