Apocalypse Revealed # 576
576. 13:3 And I saw one of its heads appearing as though fatally wounded. This symbolically means that this point of doctrine, which is at the head of all the rest, that a person is justified and saved by faith alone apart from works of the law, does not accord with the Word, in which works are so often commanded.
One of its heads symbolizes the principal and fundamental point of the entire doctrine of the Protestant Reformed Church; for the beast had seven heads, which symbolize irrationality resulting from absolute falsities (no. 568), thus also all their falsities in their entirety, inasmuch as the number seven in the Word symbolizes all (nos. 10, 390). And because their doctrinal falsities regarding salvation all depend on this one, that a person is justified and saved by faith alone apart from works of the law, that is the one symbolized here by one of the beast's heads.
Its appearing as though fatally wounded means symbolically that it does not accord with the Word, in which works are so often commanded. For every tenet of the church's doctrine that does not accord with the Word is not sound, but is sick with a deadly disease, inasmuch as the doctrine of the church must come from the Word and from nowhere else.