It has been said that ‘the Bible without the Holy Spirit is like a sun-dial at night.’

J.I. Packer has written:-

‘The Spirit’s witness to Scripture is like his witness to Jesus, which we find spoken of in Jn 15:26 and 1 Jn 5:7. (cf. 1 Jn 2:20,27) It is a matter not of imparting new information but of enlightening previously darkened minds to discern divinity through sensing its unique impact – the impact in the case of the Jesus of the gospel, and in the other case of the words of Holy Scripture. The Spirit shines in our hearts to give us the light of the knowledge of the glory of God not only in the face of Jesus Christ (2 Cor 4:6) but also in the teaching of Holy Scripture. The result of this witness is a state of mind in which both the Saviour and the Scriptures have evidenced themselves to us as divine – Jesus, a divine person; Scripture, a divine product – in a way as direct, immediate, and arresting as that in which tastes and colours evidence themselves by forcing themselves on our senses. In consequence, we no longer find it possible to doubt the divinity of either Christ or the Bible.

‘Thus God authenticates Holy Scripture to us as his Word – not by some mystical experience or secret information whispered into some inner ear, not by human argument alone (strong as this may be), nor by the church’s testimony alone (impressive as this is when one looks back over two thousand years). God does it, rather, by means of the searching light and transforming power whereby Scripture evidences itself to be divine. The impact of this light and power is itself the Spirit’s witness “by and with the Word in our heart.” Argument, testimony from others, and our own particular experiences may prepare us to receive this witness, but the imparting of it, like the imparting of faith in Christ’s divine Saviourhood, is the prerogative of the sovereign Holy Spirit alone.

‘The illumination of the Spirit witnessing to the divinity of the Bible is universal Christian experience, and has been so from the beginning, though many Christians have not known how to verbalise it or to handle the Bible in a manner consistent with it.’

(Concise Theology)