Ibbur (), is one of the forms of transmigration of the soul and has similarities with gilgul neshamot "reincarnation of souls" in Rabbinic Judaism.
ÿIbbur is the most positive form of possession and the most complicated. In contrast, possession by a dybbuk () is highly adverse and requires exorcism. It happens when a righteous soul decides to occupy a living person's body for a time, and joins, or spiritually "impregnates" the existing soul. ÿIbbur is always temporary; the possessed person may not know it has occurred. An ÿibbur is often believed to require consent from the possessed. The reason for an ÿibbur is always benevolentâÂÂthe departed soul wishes to complete an important task, to fulfil a promise, or to perform a mitzvah (a religious duty) that can only be accomplished in the flesh. In Lurianic Kabbalah, ÿibbur occurs when an incomplete soul that cannot achieve tiqqun ("rectification") is completed by the addition of the soul of a tzadik "saint". Luria believed this to be possible even if the possessor were still alive.