What is your opinion of those who say we have no need to study the methodologies of the Mu'tazilah and the Jahmiyyah because they have passed away?

Question:
Honorable Shaykh, may Allah grant you success. Some people say we have no need to study the methodologies of the Mu'tazilah, the Jahmiyyah, and the like, because they have passed away.

Answer:
We study them because we need to. We study them to know them, in order to worship Allah and to warn against them. Otherwise, praise be to Allah, we have no need for them. The Book of Allah and the Sunnah of His Messenger, and what this Ummah is upon, is sufficient for us. So we do not study them because we need them, but rather we study them because we need to know them, so that they do not spread among the people, in order that we may warn against them.
Especially since there are now people who call to them, printing the books of the Mu'tazilah, editing them, and publishing them. So if we do not know their methodology and their doubts, they may deceive us and our ignorant people. Therefore, this is necessary, for whoever does not know the Shari'ah falls into it. Yes.