The Founder: Jesus of Nazareth
Christianity has a historical founder whose existence is verified by outside sources. The most reliable of these sources is the account from Josephus, a first-century Jewish historian born in Jerusalem, who eventually became a Roman citizen. In his work, Antiquities of the Jews, he makes several brief references to Jesus, both as a Messiah and as a wise teacher. Josephus also records that Jesus was crucified, and that his followers believed he was restored to life. Beyond that, however, history is silent.
The most information about Jesus is recorded in four books of the Bible: Matthew, Mark, Luke, and John. It is important to note here, however, that these books were not written as biographies; their purpose rather was to persuade others that Jesus was the son of God and the savior of the world. Thus, they describe the life and ministry of Jesus as the one they believed was God in the flesh. In other words, what we have in these four books of the Bible is an account of Jesus the Christ—that is, “the anointed one” or “the chosen one”—not a history of Jesus the man from Nazareth.
What do Christians Believe about Jesus?
First and foremost, Christians believe that Jesus is both fully human and fully divine: the technical formula is “one person, two natures.” Christians believe Jesus was neither just another enlightened teacher on the one hand, nor a divine avatar on the other—God in a human disguise. Instead, in all his words and deeds, Jesus was both fully and completely divine and also a real, embodied human being. The language Christians use to describe this is “incarnation.” That is, Christians believe God became “incarnate”—literally, “in-fleshed”—in one human being, Jesus of Nazareth, son of a young woman named Mary, and her husband, Joseph.
Second, in Jesus, Christians believe they have the clearest expression of God’s core nature, and how God wants to be in relationship with humanity and the world. This is why Jesus’ life—his ministry, his friends, his disciples—all are crucial to a Christian understanding of God. Christians believe that the fundamental disposition of God toward creation is love, and that everything God does in the world is meant to manifest that love. In his person and in every act of his human life, Jesus is thought to embody that love.
Another point needs to be mentioned here as it relates to Jesus’ life and ministry, and that is that Jesus was very transgressive, repeatedly violating social norms and “queering” traditional notions of power and social status. He did not align himself with the Pharisees, the Jewish authorities of the time; indeed, they received regular and repeated chastising from Jesus for their emphasis on rules over people. Instead, Jesus surrounded himself with tax collectors, prostitutes, and other questionable members of society, welcoming children onto his lap, healing lepers, and conversing with strange women. Over and over again, Jesus aligned himself with outsiders: with the poor and the polluted, the underprivileged, and the unwanted.
Like the followers of many religions, Christians have a sacred text, the Bible, which is a compilation of many smaller texts written by many authors, only some of whose identities are known. The Bible is often described by Christians as being “inspired,” although that word has been interpreted in different ways. While some Christians believe that the Bible should be read literally, even as regards matters of science and history, mainline Christians believe that the Bible was not written as a science textbook, biography, or historical account, but instead, as witness to the one God who revealed Godself in history in a covenantal relationship first with the Jewish people, and then, through Jesus Christ, to the whole world. This leaves open the possibility for harmonizing the Christian story with new discoveries in geology, anthropology, history, astronomy, etc., etc.
The Christian Bible is divided into two major sections, which traditionally have been called the Old Testament and the New Testament. The number of books in the Bible varies among different Christian denominations, but the two main divisions are between the Catholic Bible, which has seventy-three books, and the Protestant Bible, which has a total of sixty-six books.
The Christian Community
The birth of the Christian community, or “the church,” usually is associated with the event recounted in the book of the Bible known as The Acts of the Apostles, when 3,000 people were baptized in Jerusalem after the extraordinary witness of Jesus’ disciples, who spoke in a multitude of foreign tongues after receiving the gift of the Holy Spirit.
When talking about the church, conversation usually begins with Paul and the various letters he wrote to the fledgling Christian communities around the Mediterranean (these letters now make up a considerable part of the New Testament). These communities were struggling with very real issues that the church still struggles with today: squabbles between Christians, questions around sexual morality, issues of discrimination during worship, and the role of the law in the life of a Christian. In many ways, these early communities prefigured the Christian church as it exists today: bound together in faith in Jesus Christ, but also separated by different interpretations of doctrines and practices, and uniquely flavored by the specific geographic and cultural context in which they developed. Today, these different church bodies typically are called “denominations,” and dialogue/partnership between them is called “ecumenical.”
The Christian community has two components that are found in almost every Christian denomination around the globe. These features are “word” and “sacrament.” “Word,” in this context, refers to the Bible: Bible readings, as well as preaching. Any community that calls itself “church” gathers around the Bible, reading and meditating on scripture.
The second feature of most churches is “sacrament.” Perhaps the most famous definition of a sacrament comes from Augustine: “visible signs of an invisible grace.” Sacraments—such as baptism and communion—are believed to be tangible experiences of God’s love and mercy that both an individual and the community receive in faith, in their physical bodies, in the greater physical body of the gathered people.
It took the church several centuries to sort out what Christians have come to consider “orthodox” church doctrine; and, even though official church teachings have been established for millennia, debates about the same questions still continue today.
The Trinity: First and foremost among Christian teachings is the doctrine of the Trinity, which is both central to an understanding of the Christian faith and also extremely difficult to explain. The doctrine of the Trinity refers to the Christian belief that the One God actually exists in three “persons”: God the Father, God the Son, and God the Holy Spirit. These “persons” are not separate, different individuals—Christianity does not profess belief in three gods—but rather, the three persons share the same essence and make God known to humanity in different ways.
Salvation: Another key Christian doctrine is salvation—the core Christian claim is that “Jesus Saves”—but what, exactly, that means continues to be debated. One of the most pressing aspects of a Christian understanding of salvation is how it relates to the way Christians view other religious traditions. The traditional Christian view regarding salvation has been that outside the Christian church, there is no salvation. This idea drove the missionary practices of the church for centuries—and still drives many different churches today: there was a strong impetus to convert people to Christianity so that they would go to heaven after they died.
However, in the 21st century, this understanding of salvation has been increasingly challenged, and the possibility of other options has been raised, particularly the possibility of universal salvation. Many people assume that this is a modern idea, brought about by engagement with a more liberal, secular society, but this doctrine actually has a long history in the Christian tradition.
Lived Christian Identity
Christian living is concerned in large part with “sanctification,” which means to grow in holiness, and “justification,” which means to be made righteous before God. In tandem, they point to two important aspects of Christian life: first being saved; and second, being transformed in light of that salvation. Different denominations use different language to describe these two concepts—and not all of them emphasize both equally
For Further Reading:
Confessions, by Augustine
Meeting Jesus Again for the First Time: The Historical Jesus and the Heart of Contemporary Faith, by Marcus Borg
A Brief Introduction to the Old Testament, by Michael Coogan
Oxford Dictionary of the Christian Church, edited by F.L. Cross and E.A. Livingstone
The Story of Christianity, by Justo Gonzalez
Blackwell Encyclopedia of Modern Christian Thought, by Alister McGrath
Faith Seeking Understanding: An Introduction to Systematic Theology, by Daniel Migliore
Introducing the New Testament: A Historical, Literary, and Theological Survey, by Mark Allan Powell
 As quoted in Daniel Migliore, Faith Seeking Understanding: an Introduction to Christian Theology, 3rd edition, (Grand Rapids, MI: Eerdmans Publishing Company, 2014), 291.