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

The Shaykh : Here is the third question in the set of questions we discussed regarding the first and second questions.
He says: Removing shoes in the cemetery, knowing that it is impure...

The questioner: Peace be upon you.

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

The questioner : Is the questioner present here?

Another questioner: Yes.

The Shaykh : What does [this] mean?

The questioner : ...that it is impure...

The Shaykh : The cemetery, I mean? What do you mean by the question? You say: Removing shoes in the cemetery, knowing that it is impure. This statement is not complete; this is the beginning of a sentence, 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 idea.

The questioner : ... .

The Shaykh : This question?

The questioner: Yes.

Another questioner: Peace be upon you.

The Shaykh : And upon you be peace, and the mercy of Allah and His blessings.
Answer: Yes, and the issue has no relation to the cemetery being impure or not impure; because the ruling—namely, the ruling on removing sandals for the one who wants to walk in the cemetery—did not come from observing that the cemetery is impure or pure, but rather from observing the respect for the dead of the Muslims. It came in "Musnad al-Imam Ahmad" and others that the Prophet (peace and blessings be upon him) saw a man walking in the cemetery with his sandals on, so he said (peace and blessings be upon him): . So whether a person walks with his sandals on, or with his leather socks, or with his bare feet, the cemetery is a cemetery; whether its ground is pure or impure. So this issue—namely, the cemetery being impure or pure—has no relation to this ruling. All that is in the matter is that the prohibition of the Messenger (peace be upon him) for a Muslim to walk in his sandals in the cemeteries of the Muslims is like his prohibition of sitting on these cemeteries; where it came in "Sahih Muslim" from the hadith of Abu Mirdad al-Ghunawi, who said: The Messenger of Allah (peace and blessings be upon him and his family) said: . Because of the humiliation it entails for them, Because of the sanctification and exaltation it entails for them, an exaltation that goes beyond the limits of Islam. And this and this all—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 observation of the cemetery being impure or pure.
Not because it is impure, but because there is an exaltation of the grave more than what is necessary, Not because it is impure, but because there is humiliation for them. Islam came with the middle path; it commands respecting the graves of the Muslims, but a respect that does not lead to exalting them to a degree 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: 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 of pus and phlegm and other disgusting or impure things are below, 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, a change in the apparent state of the thing that is exposed to these natural elements.
And from this, one of the legal rulings in some Islamic schools of jurisprudence, such as the school of Abu Hanifah, is 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 decomposes. It is originally a dead, forbidden, impure carcass, and with the elements of nature, its reality changes and it becomes salt, which you eat just as you eat natural or industrial salt, so it becomes lawful and it becomes pure. This is transformation, or the change of a thing from one essence to another essence.
So if the essence is originally impure, then its reality changes and it becomes another reality, this other reality is looked at according to its current state, not according to what it was in its origin. This visible ground of the cemetery has no apparent impurity; the impurity may be below. Therefore, what is said that the cause of the prohibition of prayer in the cemetery is impurity, this statement is not correct religiously. The cause of the prohibition of prayer in the cemetery is like the cause of the prohibition of praying toward the grave itself. The grave is far from you and you are praying toward 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 with your prayer someone other than Allah (Mighty and Majestic). Likewise, the prohibition of prayer 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 be upon him) ordered the one who was walking in his sandals in the cemetery to remove them, so we took from that that one of 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 toward their dead after their burial.