Here’s another quote from Waddell’s book. It begins with a quote from the Solid Declaration, article X. The translation I’ve pasted here differs from the one Waddell used.
14] For here it is no longer a question concerning external matters of indifference, which in their nature and essence are and remain of themselves free, and accordingly can admit of no command or prohibition that they be employed or omitted; but it is a question, in the first place, concerning the eminent article of our Christian faith, as the apostle testifies, that the truth of the Gospel might continue, which is obscured and perverted by such compulsion or command, because such adiaphora are then either publicly required for the sanction of false doctrine, superstition, and idolatry, and for the suppression of pure doctrine and Christian liberty, or at least are abused for this purpose by the adversaries, and are thus viewed [and are believed to be restored for this abuse and wicked end].
Note how the statement, “For in such a case it is no longer a matter of external adiaphora,” can not mean that adiaphora cease to be adiaphora in a state of confession, as Matthias Flacius had argued, because the confession explicitly maintains that adiaphora “in their nature and essence are and remain in and of themselves free.” This goes directly against Flacius’ contention that in the context of confession adiaphora cease to be adiaphora. The formulators argue here that in a state of confession the issue shifts from being about adiaphora to being about the gospel.