As an integral part of the Prison Letters, Paul wrote Colossians to reinforce the believer’s faith.
The church was in dange of becoming extinct, because it was trapped in an error that Paul calls an outside “philosophy” (2:8, 16-23), which treatened their assurance. This error was not a heresy or some kind of false doctrine. The most one can say is that the error devalued Christ’s supremacy and the adequacy of salvation thorugh him.
The congregation, therefore, needed encourangement about the certainty of their faith. Against this treat, Paul argues for the all-sufficiency of Christ by asserting 3 truths:
all the fullness of deity dwells in Christ
believers are complete in Chirst, &
Christ has authority over all angelic beings and cosmic powers (2: 9-15)