Purgatorial Universalism was the belief of some of the early church fathers, especially Greek-speaking ones such as Clement of Alexandria, Origen, and Gregory of Nyssa. It asserts that the unsaved will undergo hell, but that hell is remedial (neither everlasting nor purely retributive) according to key scriptures and that after purification or conversion all will enter Heaven. Judaism teaches something similar – hell is an intense experience of cleansing, more an expression of kindness than a punishment.[13]