Pleroma is a Greek word that has to do with filling or being full, or completing or being complete. The word in various conjugations is common in the New Testament and is used in a variety of contexts. In Matthew 1:22 it is translated “to fulfill (prophecy),” and in Matthew 13:48 it is used to describe a full net of fish. In Acts 2:2 the sound of the rushing wind “filled” the house, and in Acts 2:28 Peter quotes David as being “full” of gladness. In non-biblical usage there are examples of pleroma being used of a “full” ship or even a “fully manned” ship. It is simply a normal Greek word without any inherent theological content.
The reason pleroma has become an issue is Paul’s use of it in Colossians 1:9 to speak of being “filled” with the knowledge of God’s will; in Colossians 1:25 to say that he is “fully” carrying out his ministry; in Colossians 2:10 to tell the believers they are “complete” in Christ; and in Colossians 4:17 to encourage someone to “complete” his ministry. These are all rather straightforward. In Colossians Paul uses the word pleroma two times in reference to Christ—each occurrence is a powerful statement of the deity of Christ. Colossians 1:19: “For God was pleased to have all his fullness dwell in him”; and Colossians 2:9: “For in Christ all the fullness of the Deity lives in bodily form.”
The fact that Paul uses the word pleroma, which later became a prominent term in Gnostic theology, has led some to infer that Paul was a Gnostic and then, in turn, to try to interpret his writings, especially Colossians, in a Gnostic fashion.
In Gnostic writings, “the Pleroma” takes on a technical meaning. The Pleroma is that spiritual perfection that is in contrast to physical deficiency. (Gnostics believed that matter was evil.) In Gnosticism, the Pleroma descended upon Christ at His baptism and left Him at the crucifixion before His death. Gnostics also hope to be able to experience the Pleroma themselves as they progress in Gnostic teaching.
In the New Testament, the pleroma is the fullness of God, the complete set of divine attributes that were incarnated in Christ. Christ is fully God and fully man and will forever inhabit a glorified human body. He is the unique Son of God in this way. Although sons of God by faith will inherit a glorified body and are complete in Christ (as in Colossians 2:10) and indwelt by the Spirit of God, Christ is unique in His deity and sonship. In Gnosticism, “the Pleroma” is a spiritual fullness or perfection that descended upon Christ temporarily and can descend upon other human beings as well. The Pleroma will never be permanently attached to a physical body because matter is considered evil—only the spiritual is good. Therefore, the Gnostic understanding the Pleroma as it applies to both the uniqueness of Christ and the goodness of created matter is at odds with biblical teaching.