Pre-existence of Christ
The pre-existence of Christ asserts the existence of Christ before his incarnation as Jesus. One of the relevant Bible passages is where, in the Trinitarian interpretation, Christ is identified with a pre-existent divine hypostasis (substantive reality) called the Logos or Word. There are nontrinitarian views that question the aspect of personal pre-existence or the aspect of divinity or both. More particularly, John 1:15,18 says: This doctrine is supported in when Jesus refers to the glory which he had with the Father "before the world existed" during the Farewell Discourse. also refers to the  Father loving Jesus "before the foundation of the world". Nicene Christianity. The pre-existence of Christ is a central tenet of mainstream Christianity. It explores the nature of Christ's pre-existence as the divine hypostasis called the Logos or Word, described in , which begins: In Trinitarianism this "Logos" is also called God the Son or the second person of the Trinity. Theologian Bernard Ramm noted that "It has been standard teaching in historic Christology that the Logos, the Son, existed before the incarnation. That the Son so existed before the incarnation has been called the pre-existence of Christ ." In the words of the Nicene Creed, Christ "came down from heaven, and was incarnate." Additionally, Trinitarian Christians see a connection between Christ and the enigmatic "angel of YHWH" figure from the Old Testament. Christian apologist David Wilber teaches that this figure is the pre-incarnate Christ:Similar to how the New Testament teaches that Jesus is distinct from God and yet also is God, the Old Testament teaches that the Angel of YHWH is distinct from YHWH and yet also is YHWH (Genesis 16:7-13; 22:15-16; Exodus 3, Judges 6, etc.). In other words, YHWH and the Angel  of YHWH are interchangeable from the Old Testament's perspective. Both are members of the one being who is God. One of those members, the Angel of YHWH, took on flesh and was born as the man Jesus.Douglas McCready, in his analysis and defense of the pre-existence of Christ, notes that whereas the preexistence of Christ "is taken for granted by most orthodox Christians, and has been since New Testament times", during the past century the doctrine has been increasingly questioned by less orthodox theologians and scholars. James Dunn, in his book "Christology in the Making", examines the  development of this doctrine in early Christianity, noting that it is "beyond dispute" that in John 1:1–18, "the Word is pre-existent, and Christ is the pre-existent Word incarnate," but going on to explore possible sources for the concepts expressed there, such as the writings of Philo. Some Protestant theologians believe that God the Son emptied himself of divine attributes in order to become human. Others reject this. Tertullian in "Against Marcion" Ch.21 sees a pre-existent appearance of Christ in the fiery furnace of one who is "like the son of man (for he was not yet really  son of man)." The identification of specific appearances of Christ is increasingly common in evangelical literature from the 1990s onwards. For example, W. Terry Whalin states that the fourth person in the fiery furnace is Christ, and that "These appearances of Christ in the Old Testament are known as Theophanies or 'appearances of God' ". Orthodox Christianity. Orthodox Christianity teaches that Jesus was personally identical with the eternally pre-existent Son of God or Logos. He did not come into existence as a new person around 5 BC but exists personally as the eternal Son of God. To adopt tensed language  from Nicaea I ("there never was [a time] when he was not" – DzH 126) According to Thomas Aquinas, "the humane nature" of Christ was created and began in time, where "the subsistent subject" is both uncreated and eternal. Manichaeism. A clear idea of Christ's pre-existence is given in Manichaean thought, where he is conferred the name Jesus the Splendour. Considered a divine being, he was believed to have been the entity to lead Adam into eating from the Tree of Knowledge instead of the Devil (AKA Prince of Darkness) who, according to Manichaeism, actually wanted humanity to stay  away from it so they would remain trapped in matter and never find gnosis. Likewise, Manichaeans associated Christ with the Tree of Life and saw him as a holy emanation of the Father of Greatness. Nontrinitarianism. Some accept the pre-existence of Christ without accepting his full divinity in the Trinitarian sense. For example, it is likely that Arius and most early advocates of Arianism accepted the pre-existence of Christ. However, Thomas Aquinas says that Arius "pretended that the Person of the Son of God is a creature, and less than the Father, so he maintained that He began  to be, saying 'there was a time when He was not.'" John Locke, William Ellery Channing and Isaac Newton appear to have maintained belief in the pre-existence of Christ despite their rejection of the Trinity. Today, several nontrinitarian denominations also share belief in some form of the pre-existence of Christ, including the Church of God (Seventh-Day) and the Jehovah's Witnesses, the latter group identifying Jesus as the archangel Michael, interpreting by translating with the phrase "a god," rather than "God". The Latter Day Saint movement teaches Christ's pre-existence as the first and greatest of  the spirit children of God the Father. Among the many churches which separated from the Worldwide Church of God, also referred to as the "Sabbatarian Churches of God" or, more pejoratively, Armstrongites, there is a shared belief in binitarianism, and that Jesus was the God of the Old Testament through whom God the Father created the world (based on Ephesians 3:9 and John 1:1–3), and that it was Jesus Christ who personally interacted with Adam and Eve, Noah, the patriarchs, ancient Israel, and the kings and prophets of the Old Testament. It is held that in his incarnation, Jesus was  sent to reveal the Father who was previously unknown. This is based on an interpretation of John 5:37, Luke 10:22, and by the large number of references Jesus made about the Father in the New Testament compared to the very few, almost figural references to God as Father in the Old Testament. This belief is also based on an interpretation of verses where Christ is believed to be discussing his personal presence in the Old Testament and interaction with ancient Israel, and on a Christological interpretation of Melchizedek. The Church of Jesus Christ of Latter-day Saints. In ways similar  to the way Orthodox Christianity views the preexistence of Christ, the belief is that the Christ that was born on this Earth is same Son of God or the Word who existed before this world. However, He is seen as having been created by God the Father. This is because within The Church of Jesus Christ of Latter-day Saints the Trinity is seen as three separate beings, each with their own bodies and personage. In reference to the doctrine of John 1:15-18, the belief continues that the God who is worshipped in the Old Testament, the Great Jehovah , is the same being who is the Son of God. During this time before Earth life, He was speaking as a representative of God the Father, which is why in some instances He refers to Himself as God the Father. This was a customary practice in Jewish culture for a representative to speak as the master in the master's place. Though this scripture makes the assertion that no man has seen God the Father it is believed within the Latter-day Saint community that God the Father and God the Son were in the presence of Adam and Eve  whilst they were in the Garden of Eden. As well as was seen by Joseph Smith in what believer refer to as the Sacred Grove in New York in 1820 in an event commonly referred to as the First Vision. Oneness Pentecostals. Oneness Pentecostals are nontrinitarian Pentecostal Christians who do not accept the pre-existence of Christ as distinguished from God the Father, believing that, prior to the incarnation, only "the timeless Spirit of God (the Father)" existed. Afterwards God "simultaneously dwelt in heaven as a timeless Spirit, and inside of the Son of Man on this earth." However, the  United Pentecostal Church International, a large Oneness denomination, says in their statement of faith that "The one God existed as Father, Word, and Spirit" prior to the incarnation. Although Oneness Pentecostals accept that "Christ is the same person as God," they also believe that "The 'Son' was 'born,' which means that he had a beginning." In other words, "Oneness adherents understand the term [Son] to be applicable to God only after the incarnation." They have consequently been described as holding an essentially unitarian position on the doctrine, and of denying the pre-existence of Christ. However, some members of the  movement deny this interpretation of their beliefs. Denial of the doctrine. Throughout history there have been various groups and individuals believing that Jesus' existence began when he was conceived. Those who consider themselves Christians while denying the pre-existence of Christ can be broadly divided into two streams. First, there are those who nevertheless accept the virgin birth. This includes Socinians, and early Unitarians such as John Biddle, and Nathaniel Lardner. Today the view is primarily held by Christadelphians. These groups typically consider that Christ is prophesied and foreshadowed in the Old Testament, but did not exist prior to his  birth. Second, there are those who also deny the virgin birth. This includes Ebionites and later Unitarians, such as Joseph Priestley, and Thomas Jefferson. This view is often described as adoptionism, and in the 19th century was also called psilanthropism. Samuel Taylor Coleridge described himself as having once been a psilanthropist, believing Jesus to be the "real son of Joseph." Friedrich Schleiermacher, sometimes called "the father of liberal theology", was one of many German theologians who departed from the idea of personal ontological pre-existence of Christ, teaching that "Christ was not God but was created as the ideal and  perfect man whose sinlessness constituted his divinity." Similarly, Albrecht Ritschl rejected the pre-existence of Christ, asserting that Christ was the "Son of God" only in the sense that "God had revealed himself in Christ" and Christ "accomplished a religious and ethical work in us which only God could have done." Later, Rudolf Bultmann described the pre-existence of Christ as "not only irrational but utterly meaningless." In art. When the Trinity is depicted in art, the Logos is normally shown with the distinctive appearance, and cruciform halo that identifies Christ; in depictions of the Garden of Eden this looks  forward to an incarnation yet to occur. In some Early Christian sarcophagi, the Logos is distinguished with a beard, "which allows him to appear ancient, even preexistent." In Eastern Orthodox theology, the Old Testament title "Ancient of Days", signifying God's eternal and uncreated nature, is commonly held to identify the pre-existence of God the Son. Most of the eastern Church Fathers who comment on the passage in Daniel (7:9-10, 13–14) interpreted the elderly figure as a prophetic revelation of the Son before his physical incarnation. As such, Eastern Christian art will sometimes portray Jesus Christ as an  old man, the Ancient of Days, to show symbolically that he existed from all eternity, and sometimes as a young man, or wise baby, to portray him as he was incarnate. This iconography emerged in the 6th century, mostly in the Byzantine Empire with elderly images, although usually not properly or specifically identified as "the Ancient of Days."