This does not refer to his direct inspiration

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THE NATURE OF THIS WORK OF THE SPIRIT

The Holy Spirit does this work by teaching ‘The unction teaches you.’ This does not refer to his direct inspiration, that is, his bringing new sacred truths from God directly to the minds of men. This is how he taught the apostles and prophets (1 Pet. 1:11-12; 2 Pet. 1:21). Nor does God grant new revelations to preserve his people from error. God has made sufficient provision in his Word for that (Isa. 8:20; 2 Pet. 1:19).

The teaching referred to is his enabling us to discern, know and understand the mind and will of God as revealed in the Scriptures.