The rejection of biblical authority is a moral issue

Commenting on WCF 1:iv:

The authority of the Holy Scripture, for which it ought to be believed, and obeyed, depends not upon the testimony of any man, or Church; but wholly upon God (who is truth itself) the author thereof: and therefore it is to be received, because it is the Word of God

R. C. Sproul notes that:

The confession asserts that the Bible's authority is so strong, so supreme, that it imposes on us a moral obligation to believe it. If we do not believe it, we have sinned. It is not so much an intellectual as a moral issue.

Throughout Church history, the supreme attack of the world, the flesh, and the devil against godliness has been an attack on the authority of God's Word. Fierce assaults on the authority of Scripture, which came out of the Enlightenment, made their way into the universities and seminaries. They also came from within the Church, in the name of biblical criticism or higher criticism.

At the end of the nineteenth century and the beginning of the twentieth, Abraham Kuyper...observed that biblical criticism had become biblical vandalism. Once, when I was in the old city of Athens, I observed people spray-painting graffiti on two-thousand-year-old ruins. "Is nothing sacred today?" I thought. No treasure has been more subject to malicious attack than Scripture itself.

R. C. Sproul, Truths We Confess: Vol. 1 The Triune God, p. 12-13