Charles Ellicott Commentary 1 Corinthians 6:17

"But he that is joined unto the Lord is one spirit." — 1 Corinthians 6:17 (ASV)

One spirit.—The union between Christ and each member of His Church is a spiritual one. This explains the sense in which we are the Lord’s body, and intensifies the argument against any degradation of one who shares so holy and intimate a union.