“Speaking the truth in love, we will grow to become in every respect the mature body of Him who is the head, that is, Christ. From Him the whole body, joined and held together by every supporting ligament, grows and builds itself up in love, as each part does its work.” (Ephesians 4:15-16 NIV)
The Church… is the body of Christ. Every Christian is a member or organ of the body, while Christ Himself is the Head, controlling the body’s activities. Not every organ has the same function, but each is necessary for the maximum health and usefulness of the body. Moreover, the whole body is animated by a common life. This is the Holy Spirit. It is His presence which makes the body one.
-- John R. W. Stott, as quoted in “Growing Strong in God’s Family: A Course in Personal Discipleship to Strengthen Your Walk with God”