From the "Lesson on Encouragement and Warning," Chapter "Encouragement of Cupping and When One Should Undergo Cupping," The Sermon of Necessity

The Shaykh : ... and among the evil of our deeds, whoever Allah guides has no one to misguide, and whom He leaves to misguide has no one to guide, and I bear witness that there is no god but Allah alone, with no partner, and I bear witness that Muhammad is His slave and His Messenger, , , , As for what follows:
Indeed, the best of speech is the speech of Allah, and the best of guidance is the guidance of Muhammad (peace and blessings be upon him and his family), and the worst of matters are their innovations, and every innovation is a religious innovation, and every religious innovation is misguidance, and every misguidance is in the Fire.
Now the author (may Allah have mercy on him) says: "Encouragement of Cupping and When One Should Undergo Cupping."
This chapter is, in reality, with regard to our time today, as if it is irrelevant, as they say; because cupping has become a forgotten thing and an un-Islamic medical practice among Muslims, unfortunately, due to their turning away from Prophetic medicine on one hand, and their immersion in Western medicine on the other. In fact, this immersion is likely the direct cause of their turning away from this Prophetic medicine, which includes cupping. I think that even if you do not see a cupper today, and consequently do not see a person being cupped, you know that cupping means extracting blood from the body. We no longer see this cupping in these days, and I experienced it; there were some barbers who practiced cupping in reality, and I underwent cupping more than once. As for today, I do not know if there are still remnants of these cuppers in the corners that we no longer hear about, or if they have disappeared and perished because Muslims today no longer believe in anything except this Western medicine based on these known medicines.
This is, in reality, an indication to the reasonable Muslim that Muslims are moving away and continuing to move away from the religion and from adopting its legislations and rulings. So listen now to some of the authentic hadiths that came with the exhortation to cupping.