Heresy
The Greek word hairesis, which first means "choice," refers to a sect or faction. For example, the Sadducees were a sect within Judaism, as were the Pharisees (Acts 5:17; 15:5). They called early believers in Jesus as the Messiah, "the sect of the Nazarenes" (Acts 24:5). In each of these verses, hairesis simply means a sect or denomination.
As the church expanded, they named any divisive group within a local church a hairesis. This term refers to a sect with beliefs opposing the truths taught by the apostles. Paul warned the Corinthian church that divisive sects would form among them (1 Corinthians 11:19).
Eventually, the word heresy came to mean teaching that departs from the norm and causes people to leave orthodoxy (traditional and established beliefs). Peter warned Christians about false teachers who would try to mislead believers with "destructive heresies" (2 Peter 2:1). Today, this is how the word heresy is usually understood. It refers to false teaching that harms the faith of some Christians and creates divisions within the church.
Two Early Heresies
Two major heresies were common in the church during the apostle John's time: Gnosticism and Docetism.
Gnosticism
Gnosticism claimed to have special and secret spiritual knowledge. Many Gnostics believed in a hierarchy of beings. At the top was an eternal god, from whom came a series of lesser spiritual beings. Among these was the creator god, considered evil. This creator god made the material world, including humans.
Similar to the teachings of the Greek philosopher Plato, these Gnostics believed everything material was evil. A more "real" spiritual realm existed. Their goal was to find the spiritual "seed" within themselves through secret "knowledge" (Greek gnōsis).
This knowledge would help them leave the physical world and join the spiritual realm. This belief led to different responses to the physical world. Some Gnostics strictly avoided physical pleasure. Others freely lived for physical desires, seeing their actions as unimportant.
Gnosticism developed by combining Christianity with Greek philosophy. It stressed the need for special knowledge that changed traditional Christian beliefs and practices. Gnostics often included Christ in their beliefs. They considered Christ as one of many "streams" from a supreme being. Many Gnostics believed that Christ taught some followers to find their inner spiritual "spark" and connect with the spiritual realm.
Many Christian writings from the first two centuries countered Gnostic false teachings.
Docetism
Docetism was a type of Gnosticism. It taught that Christ only seemed to have a human body with physical birth, death, and resurrection. Dokeō is a Greek verb meaning “to seem.”
An early Docetist named Cerinthus claimed that the spiritual "Christ" joined the human Jesus at his baptism. He stayed during his ministry but left before his suffering and death. This movement hoped to protect God's divinity from being stained by Jesus' human nature. According to early church tradition, the apostle John strongly opposed Cerinthus' teachings (see Irenaeus, Against Heresies 3.3.4; compare 1 John 5:5–8; 2 John 1:7).
True Christians believe in the Incarnation when God became a real human with flesh and blood in the person of Jesus of Nazareth. Jesus' humanity was real. He was truly human, sharing our flesh and blood, so he could save humanity through his own flesh and blood.
Ignatius was a student of the apostle John and later the bishop of Antioch. He wrote letters against Docetism. Ignatius was the first person after the New Testament writers to mention Jesus' virgin birth. He also stressed that the apostles touched the body of their risen Lord. Ignatius said he could face martyrdom (dying for one's beliefs) bravely because of Jesus Christ's real suffering on the cross and his physical resurrection.
Passages for Further Study
Acts 8:9–24; 2 Corinthians 11:1–15; Colossians 1:23; 2:6–23; 1 Timothy 6:20; 2 Peter 2:1–22; 1 John 4:2–3; 5:5–8; 2 John 1:7–11; 3 John 1:9–12; Revelation 2:2, 14–16, 20–25