What is the ruling on taking dead bodies for dissection for educational purposes, and stealing or purchasing them from graves?

It is not permissible to exhume a grave and remove the deceased from it, due to the sanctity of a Muslim, whether alive or dead. The proof for this is the saying of the Messenger of Allah, peace and blessings be upon him: "Breaking the bone of a dead person is like breaking the bone of a living person." Similarly, selling corpses is not permissible.