Middle Ages, the theory was systematically taught by the Schoolmen such as Bonaventure. Trinity and love Augustine "coupled the doctrine of the Trinity with anthropology. Proceeding from the idea that humans are created by God according to the divine image, he attempted to explain the mystery of the Trinity by uncovering traces of the Trinity in the human personality". The first key of his exegesis is an interpersonal analogy of mutual love. In (399–419) he wrote, The Bible reveals it although only in the two neighboring verses 1 John 4:8.16, therefore one must ask if love itself is triune. Augustine found that it is, and consists of "three: the lover, the beloved, and the love." Reaffirming the theopaschite formula (meaning "One of the Trinity suffered in the flesh"), Thomas Aquinas wrote that Jesus suffered and died as to his human nature, as to his divine nature he could not suffer or die. "But the commandment to suffer clearly pertains to the Son only in His human nature. ... And the way in which Christ was raised up is like the way He suffered and died, that is, in the flesh. For it says in 1 Peter (4:1): 'Christ having suffered in the flesh' ... then, the fact that the Father glorifies, raises up, and exalts the Son does not show that the Son is less than the Father, except in His human nature. For, in the divine nature by which He is equal to the Father." In the 1900s the recovery of a substantially different formula of theopaschism took place: at least (meaning "not only in the flesh"). Deeply affected by the atomic bombs event, as early as 1946 the Lutheran theologian Kazoh Kitamori published Theology of the Pain of God, a theology of the Cross pushed up to the immanent Trinity. This concept was later taken by both Reformed and Catholic theology: in 1971 by Jürgen Moltmann's The Crucified God; in the 1972 "Preface to the Second Edition" of his 1969 German book (English translation: ) by Hans Urs von Balthasar, who took a cue from Revelation 13:8 (Vulgate: , NIV: "the Lamb who was slain from the creation of the world") to explore the "God is love" idea as an "eternal super-kenosis". In the words of von Balthasar: "At this point, where the subject undergoing the 'hour' is the Son speaking with the Father, the controversial 'Theopaschist formula'