from the article;
11. Because we believe that faith is the gift of God (Ephesians 2:8) and that all those who call upon the name of the Lord will be saved (Romans 10:13), we have scriptural reasons to presume that all professing believers are true children of God. But because a profession of faith is subjective, there will be false believers in our midst. What is their relation to Christ’s covenant? Objectively, there is none. They do not belong to Christ, supposing they never repent and believe.
However, they are held accountable for their treason. When a spy is discovered, a country should not release him to his own land under the false notion that they do not have authority over him. Quite to the contrary, the spy is accountable to the laws of the land in which he committed his crimes. So also, false believers are not released without action. They are accountable to the King, Jesus Christ, and they are to be removed from the body of Christ by excommunication. The warning passages of Scripture cause the sheep to flee to Christ and the goats to flee from Christ.