Spirit Possession of Spirits of the Sages

According to Jewish tradition we all are, upon birth, gifted a Divinely-derived spirit. There are five aspects to this spirit, listed in order of most immaterial to most physical. They are: the Yehidah, the Chiya, the Neshemah, the Ru'ah, and the Nefesh.  When you die, four of the five aspects quickly return to the pool of Divine spirit, but the Nefesh lingers, “leaking” out of the body over a period of 24 hours, transitioning from a spirit of the living to a spirit of the dead.  Once liberated from the body the Nefesh becomes a purely spiritual entity. The Nefesh may journey to Sheol, meeting place of the recently dead, if the messengers find it free of unresolved transgression, that is, a tzaddik - a pure and righteous person, one who has rectified all transgression.

A Maggid (plural maggidim) is a departed tzaddik and usually a sage. The Rabbi Moshe Cordovero, writing in the third quarter of the 16th century, stated in his Drishot be-Inyane ha-Malakhim (Inquiries Concerning Angels) the “the types of ibbur (cling) depends on a person's moral and spiritual state, whether his Nefesh may cling to a maggid spirit if righteous".   Rabbi Hayyim Vital (1542-1620) in his book Shar'are Kedushah, expounds: “Seclude yourself in an isolated place, wrap yourself in a prayer shawl, sit and close your eyes, divesting yourself of the material world as if your Nefesh had left your body and were ascending. Following this abstraction, recite whatever single Mishnah that you wish, many times in uninterrupted succession. Cling to the Nefesh of the sage.... He will speak with your mouth and your will hear with your ears the wisdom of the words.” 

In summary, the Jewish literature contains accounts of spirit possession exercised between the great sage and prophets and tzaddiks spanning continuously over 3000 years.  It was not a theoretical practice, rather one regularly used to give the opportunity of spirits of the dead an opportunity to impart wisdom.