In God's mind, and according to His eternal purposes, the Lord Jesus Christ is incomplete without His church.
"God... hath put all things under His feet, and gave Him to be the head over all things to the church, which is His body, the fullness of Him that filleth all in all" (Ephesians 1:17; 22-23).
It was said of the first man, Adam, that "it is not good that the man to be alone" (Genesis 2:18). Eve was therefore created, requiring the wounding and healing of Adam for her to be formed. "And the LORD God caused a deep sleep to fall upon Adam and he slept: and He took one of his ribs, and closed up the flesh instead thereof" (Genesis 2:21). This foreshadowed and typified the suffering, death, and resurrection of the Lord Jesus, from whom came forth the spiritual bride that comprises all born again believers in Him. We are "the fullness of Him" because God's eternal purpose in Christ determined that His Son should be spiritually united to Christians in a relationship wherein He is the Head, and we are the body.
"As the body is one and hath many members, and all the members of that body, being one many, are one body, so also is Christ" (I Corinthians 12:12).
Note that the Head and the body are both referred to in the Apostle Paul's description of "Christ." We mean nothing heretical by this observation, and Paul was certainly not proposing that the Lord Jesus and the church are intrinsically the same. Nor is it that case that the Apostle meant to counter the Biblical declaration of God's perfect self sufficiency (Acts 17:25). He rather alluded to the intimacy and nearness of union between Christ and the church, as in human marriage wherein two parties become "one flesh," but remain distinct in their being and personhood (Ephesians 5:31). God Himself has ordained such union between our Lord and ourselves, and therefore views us as inseparable and incomplete without each other. We are "in Christ" spiritually, He is in us, and we must never view our Lord or ourselves apart from this wonderful truth of the most sublime grace. "And I will pray the Father, and He shall give you another Comforter, that He may abide with you for ever" (John 14:16).
"Because ye are sons, God hath sent forth the Spirit of His Son into your hearts, crying, Abba, Father" (Galatians 4:6). We may not always live accordingly, but nothing ever changes the fact of our spiritual union with the Lord Jesus. Grace has given to us a gift of such magnitude and proportion that it is difficult to conceive the wonder of it. Believing the truth, however, will increasingly change our lives as we realize the living presence of the One with whom we live both now and forever. "Reckon ye also yourselves to be... alive unto God through Jesus Christ our Lord" (Romans 6:11). As I mentioned to a friend yesterday, "We are nothing without Him. But we are not without Him!" Again, if we have believed, Christ is in us, and we are in Him. Let us go forth to meet this day, this lifetime, and forevermore in the light of our being "complete in Him," and in the wonder of His being completed by us (Colossians 2:10).
"He that is joined unto the Lord is one spirit."
(I Corinthians 6:17)