"Scripture will ultimately suffice for a saving knowledge of God only when its certainty is founded upon the inward persuasion of the Holy Spirit. Indeed, these human testimonies which exist to confirm it will not be vain if, as secondary aids to our feebleness, they follow that chief and highest testimony. But those who wish to prove to unbelievers that Scripture is the Word of God are acting foolishly, for only by faith can this be known."