Who Are Members of the Church?
If, as we have seen, salvation is the process of entering the church, it follows that no one is in the church who does not have salvation. The church is one “family in heaven and earth,” (Ephesians 3:15) named from the Father. This family is “the household of God.” (Ephesians 2:19)
Therefore it follows that only the sons of God, such as are born of the Spirit, are in the church. And we are told that “He that committeth sin is of the devil,” and “Whosoever is born of God doth not commit sin…. In this the children of God are manifest, and the children of the devil” (1 John 3:8-10)—namely, in the fact that children of the devil commit sin, and the children of God do not. The holy apostle repeats the fact with emphasis: “We know that whosoever is born of God sinneth not; but he that is begotten of God keepeth himself, and that wicked one toucheth him not.” (1 John 5:18)
There are no sinners in the church. But all sects are more or less filled with sinners. Hence, no sect is the church of God.