What is the evidence that the ghusl is specific?

Question : Now, what is the evidence that this ghusl is specific?

Answer : The evidence is the saying of Allah the Exalted: And Allah did not mention anything other than that, namely to purify oneself. And if a person washes his entire body with water once, it is true that he has purified himself, is that not so? Yes.
If you say that this verse is general and the Prophet (peace and blessings be upon him) specified it, specifying this generality by his action, then the ghusl becomes obligatory in the manner in which the Prophet (peace and blessings be upon him) used to perform it. Because when Allah said "Establish the prayer," which is a general command, the Prophet (peace and blessings be upon him) explained it by his action, so it became obligatory for us to establish the prayer as the Messenger (peace and blessings be upon him) did. Here, when He said "Purify yourselves" and did not clarify the manner in the Qur'an, but the Messenger (peace and blessings be upon him) clarified it, we know that it is obligatory for us, or that the situation necessitates that it is obligatory for us, to do as the Messenger (peace and blessings be upon him) did. Did you understand this or not? Now, what is the answer?
We said the answer is from two or three angles. First, if Allah the Mighty and Majestic had wanted us to perform ghusl in a specific detailed manner, He would have clarified it as He clarified how to perform wudu in a detailed manner. Since He clarified wudu in a detailed manner and left this one general, we know that it is not obligatory to start, for example, with the upper part of the body, or the right side, or the left side. This is one point.
Second, the Prophet (peace and blessings be upon him) said to the man who was performing tayammum and not praying—rather, the man who had contracted major ritual impurity and was not praying—he said to him: The story is well known and established in Sahih al-Bukhari in the long hadith of 'Imran ibn Husayn. There was no water with the people, and 'Ali ibn Abi Talib and a man with him went to look for water. Water arrived, and the people drew from it and purified themselves, and a remainder was left. So the Prophet (peace and blessings be upon him) said: He does not pray. He said to him: "Take the dust, for it is sufficient for you." He said to him: "Take this and pour it over yourself." And the Prophet (peace and blessings be upon him) did not clarify to him how to pour it over himself. If the ghusl had been obligatory in the manner in which the Messenger (peace and blessings be upon him) performed it, he would have clarified it to him. Because delaying clarification until the time of need is not permissible in the context of conveying the message, and it is obligatory upon the Messenger (peace and blessings be upon him) to convey the clear message. And this man appears to be [unclear], because if someone were to say, perhaps this man knew the manner of ghusl, we would say the default is that he did not know it. Moreover, the apparent state of his condition is that he was an ignorant man, as evidenced by the fact that he did not know that tayammum suffices for ghusl when water is absent.