What is one of the many roles of the Holy Spirit? The Holy Spirit performs a didactic and illuminating function. In the Old Testament the psalmist wants the Spirit to lead and teach him. The Holy Spirit does exactly that.
Teach me to do your will, for you are my God! Let your good Spirit lead me on level ground!
English Standard Version (Wheaton, IL: Crossway Bibles, 2016), Psalm 143:10
The role of the Spirit is to teach Jesus’ disciples the things they need to know to follow him. Disciples are learners and students. Our teacher is the Holy Spirit as revealed to us in scripture.
But the Helper, the Holy Spirit, whom the Father will send in my name, he will teach you all things and bring to your remembrance all that I have said to you.
English Standard Version (Wheaton, IL: Crossway Bibles, 2016), Jn 14:26
And this is very encouraging. The Holy Spirit guides in ALL truth. Not just some but all. As the third member of the trinity, the Holy Spirit knows the mind of God and Jesus. There are no secrets with the Holy Spirit. The Holy Spirit is in on everything, soup to nuts!
When the Spirit of truth comes, he will guide you into all the truth, for he will not speak on his own authority, but whatever he hears he will speak, and he will declare to you the things that are to come.
English Standard Version (Wheaton, IL: Crossway Bibles, 2016), Jn 16:13
He is given specifically so that God’s people “may understand what God has freely given us”
And we impart this in words not taught by human wisdom but taught by the Spirit, interpreting spiritual truths to those who are spiritual.
English Standard Version (Wheaton, IL: Crossway Bibles, 2016), 1 Co 2:13
This is why Calvin saw the role of the Holy Spirit as being “to seal on our minds the very doctrine which the gospel recommends” (Institutes 1.9.1).
Good news: This is all stunning. We have the power of the Holy Spirit in us. We have been immersed in the Holy Spirit. We have the gifts of the Holy Spirit.
Michael F. Bird, Evangelical Theology: A Biblical and Systematic Introduction (Grand Rapids, MI: Zondervan, 2013), 632.