WCF 1.4.
The authority of the Holy Scripture, for which it ought to be believed, and obeyed, dependeth 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. (2 Pet. 1:19, 21, 2 Tim. 3:16, 1 John 5:9, 1 Thess. 2:13)