Pre-existence
Pre-existence, preexistence, beforelife, or premortal existence, is the belief that each individual human soul existed before mortal conception, and at some point before birth enters or is placed into the body. Concepts of pre-existence can encompass either the belief that the soul came into existence at some time prior to conception or the belief that the soul is eternal. Alternative positions are traducianism and creationism, which both hold that the individual human soul does not come into existence until conception. It is to be distinguished from preformation, which is about physical existence and applies to all  living things. Ancient Greek thought and Islam affirm pre-existence, but it is generally denied in Christianity. Ancient Greek thought. Plato believed in the pre-existence of the soul, which tied in with his innatism. He thought that we are born with knowledge from a previous life that is subdued at birth and must be relearned. He saw all attainment of knowledge not as acquiring new information, but as remembering previously known information. Baha'i Faith. Baháʼí literature refers in a number of places to at least four key dimensions of pre-existence. Firstly, that the individual soul of a human  being comes into being at the time of conception and only thereafter is eternal; in other words it is not pre-existent. Secondly, in distinction to the above, that the souls of the world's greatest spiritual teachers, the founders of world religions, are pre-existent. Thirdly, that God, a reality which human consciousness can not comprehend, is pre-existent, that is he exists prior to time and to his creation. Fourthly, that the relationship between God and the phenomenal or contingent world is one of emanation, as the rays of the sun are to the earth. In other words , the pre-existent world of God remains separate from and does not descend into his creation. Buddhism. In Buddhist cosmology, saṃsāra is the cycle of life and death. When a person dies in earth its human soul is born into the Naraka (underworld or the "purgatories" of the souls) and afterwards it is reborn on earth. Yama, a dharmapala (wrathful god), is said to judge the dead and preside over the Narakas and the cycle. A being is born into a Naraka as a direct result of its accumulated actions (karma) and resides there for a finite period of time  (it varies from hundreds of millions to sextillions of years, but these periods are equivalent to hours or even years in earth time) until that karma has achieved its full result. After its karma is used up, it will be reborn in one of the higher worlds as the result of karma that had not yet ripened. The cycle is completed or finished when the soul reach the Nirvana. Chinese mythology. In Chinese mythology the Naihe Bridge (奈何桥), also called the Bridge of Forgetfulness), connects earth with the Diyu ("earth prison"), that is the realm of the dead or purgatory . It is typically depicted as a subterranean maze with various levels and chambers, to which souls are taken after death to atone for the sins they committed when they were alive. The number of levels in Diyu it is said to be three, four, ten or even Eighteen "courts", each of which is ruled by a judge, collectively known as the Yama Kings. The god of the dead is King Yan, it oversees the kings of the courts. Ox-Head and Horse-Face are the guardians of Diyu, and their role is the capture of human souls who have died  and bring them before the courts of Hell, where they are rewarded or punished based on the actions performed in their lifetime. Legend has it that the dead who have committed serious sins in life cannot cross the Naihe Bridge and will be pushed into the "Blood River Pool" by Ox-Head and Horse-Face to suffer the torture of insects, ants and snakes, while the dead who have done good deeds will be able to cross the bridge very easily. The goddess of forgetfulness, Meng Po, serves Meng Po Soup (孟婆汤) on the Naihe Bridge. This soup wipes  the memory of the persons before cross the bridge so they can reincarnate into their next life without the burdens of the previous life. She awaits the dead souls at the entrance of the 9th round (Fengdu). In some variations she is referred as Lady Meng Jiang Christianity. A concept of pre-existence was advanced by Origen, a second and third-century church father. Origen believed that each human soul was created by God at some time prior to conception. Church Fathers Tertullian and Jerome held to traducianism and creationism, respectively, and pre-existence was condemned as heresy in the  Second Council of Constantinople in AD 553. Origen referenced Romans 9:11-14 as evidence for his position: Origen argued that God could not love Jacob and hate Esau until Jacob had done something worthy of love and Esau had done something worthy of hatred, therefore, this passage only means that Jacob and Esau had not yet done good or evil "in this life" and their conduct "before" this life was the reason why Esau would serve Jacob. Origen also referenced Jeremiah 1:5: