Gnosticism is an umbrella term applied to a variety of early Christian sects, texts, and beliefs that would ultimately be deemed heretical. In general, Gnosticism stressed a marked duality between the material world, regarded as evil, and the spiritual world, associated with the divine. “Salvation,” in this schema, typically takes the form of enlightenment—rediscovering the truth of humanity’s divine nature, with Jesus as a prototype but not uniquely the son of God. Gnosticism was likely influenced by preexisting philosophies and religions (e.g., Platonism) and, due to its emphasis on transcendent personal knowledge, is often associated with Christian mysticism (although there is also a tradition of mysticism within the orthodox Christian sects).

Several of the texts that Pagels discusses (the Gospel of Philip, the Gospel of Truth, etc.) are Gnostic, suggesting the diversity of early Christian belief. Pagels suggests that Gnosticism’s more “democratic” understanding of divinity, coupled with its emphasis on individual experience over church doctrine, tended toward greater inclusivity than what came to be mainstream Christianity. At the same time, Pagels traces Gnostic-like elements of orthodox Christian scripture and belief (e.g., Paul’s spiritual visitation by Jesus), thus demonstrating that even apparently settled doctrine supports multiple interpretations.

This term refers to the Gospel of John’s distinct presentation of Jesus as the divine Logos, or “Word,” who “became flesh.” Pagels argues that in John’s narrative, Jesus’s identity as a divine being eclipses the content of his message, as evidenced through the use of “I am” sayings and his declarations of unity with the Father. This focus fundamentally shifts the gospel’s core requirement away from the ethical and apocalyptic summons of the kingdom and toward the act of believing “in him” to achieve spiritual rebirth. This reorientation creates a sharper boundary between believers and outsiders, with John’s Jesus stating that those who do not believe “are already condemned” (John 3:18). This view of Jesus’s nature became the decisive scriptural foundation for later doctrinal formulations about his divinity, most notably the Nicene Creed.

The “Kingdom of God” is Jesus’s core proclamation, though Pagels argues that it is interpreted in radically different ways across the gospels. In Mark, the earliest account, the kingdom is an imminent apocalyptic event requiring an urgent response. Matthew builds on this by tying entry into the kingdom to the practice of radical ethics and compassion, making one’s treatment of others the basis for final judgment. Luke introduces a more complex tension, portraying the kingdom as both a future hope and a power that is “already” present among believers on earth, a concept often described as an “already/not yet” reality.

Other texts, canonical and otherwise, push the interpretation even further. The Gospel of Thomas, for example, internalizes the kingdom entirely, defining it as a state of spiritual awareness and divine light accessible in the present through self-knowledge. In a final, decisive shift, the Gospel of John largely replaces the kingdom as the central theme. Instead, it focuses on the necessity of believing in the person of Jesus himself for salvation. The varying interpretations of this single concept allow Pagels to compare the distinct theological aims of each gospel and trace how Jesus’s message was continually adapted to meet the needs of different communities.

The “Lamb of God” is an epithet for Jesus found in the Gospel of John, where John the Baptist proclaims Jesus the “Lamb of God, who takes away the sin of the world” (John 1:29). Pagels elaborates on the theological framework underpinning the descriptor, explaining that the identification of Jesus with the Passover lamb supports the interpretation of his crucifixion as a sacrificial death that atones for the sins of the world. The Gospel of John further reinforces this imagery by aligning the timing of Jesus’s sentencing with the noon slaughter of lambs for the Passover meal and noting that his bones were not broken, echoing instructions from Exodus. The apostle Paul had earlier established this connection, declaring that “Christ, our Passover is sacrificed for us” (1 Corinthians 5:7). This understanding of Jesus’s death as a required blood sacrifice is challenged, however, by other early Christian texts like the Gospel of Truth, which presents his death not as atonement but as a revelation of divine love.

The Nicene Creed, formulated in 325 CE at the Council of Nicaea, is a proclamation of the core elements of modern Christian doctrine; in many denominations, it is recited as part of religious services. For Pagels, the most significant element of the Nicene Creed is its codification of belief in Jesus’s divinity and status as “begotten” of God the Father. This rendered heretical sects like Arianism, which held that the Son was “made” by the Father and not coeternal. Pagels contextualizes this move in terms of Roman imperial politics: Constantine, the first Christian emperor of Rome, convened the council due to frustration with ongoing disputes regarding the nature of Jesus. It was his understanding, influenced by Irenaeus of Lyons and the Gospel of John, that prevailed, and because of Christianity’s newfound entwinement with Rome, the Nicene Creed became a tool of empire wielded to shore up Rome’s power.

The Passion, from Latin patior, meaning to suffer or endure, refers to accounts of Jesus’s capture, imprisonment, trial, torture, execution, and subsequent resurrection. Passion narratives take different forms, some detailing Jesus’s triumphant entry into Jerusalem to the cheering of crowds, while others begin at his detainment by hostile forces in the Garden of Gethsemane. Passion narratives, sometimes called the Easter stories, are central to all Christian denominations, though the events they choose to include and how they choose to interpret them can range widely. 

The Passion narrative often acts as a counterpart to the nativity narrative, also known as the Christmas story. Though the four canonical New Testament gospels don’t always include the nativity stories, they all center the Passion narrative as a fundamental part of Jesus’s story. This indicates the importance of Jesus’s death to the early Christian movement as well as contemporary Christianity in all its forms.