". . .As for the false Church, she ascribes more power and authority to herself and her ordinances than to the Word of God, and will not submit herself to the yoke of Christ. Neither does she administer the sacraments as appointed by Christ in His Word, but adds to and takes from them, as she thinks proper; she relieth more upon men than upon Christ; and persecutes those, who live holily according to the Word of God, and rebuke her for her errors, covetousness, and idolatry. These two Churches are easily known and distinguished from each other."—Belgic Confession, Article 29
The "problem" of the article of our Confession of Faith quoted above is its absolute distinction between the true church and the false church. It does not speak of purer and less pure churches, of manifestations of Jesus' body that vary in degree of faithfulness and doctrinal purity; but of "two Churches," the true and the false.