Colossians 2:8 Beware lest any man spoil you through philosophy and vain deceit, after the tradition of men, after the rudiments of the world, and not after Christ.
9 For in him dwelleth all the fulness of the Godhead bodily.
10 And ye are complete in him, which is the head of all principality and power:
11 In whom also ye are circumcised with the circumcision made without hands, in putting off the body of the sins of the flesh by the circumcision of Christ:
12 Buried with him in baptism, wherein also ye are risen with him through the faith of the operation of God, who hath raised him from the dead.
We are complete in Christ by faith in Him, His work on the Cross and His powerful resurrection from the dead.