1 Corinthians 2:9-16 9But, as it is written, "What no eye has seen, nor ear heard, nor the heart of man imagined, what God has prepared for those who love him"— 10these things God has revealed to us through the Spirit. p> For the Spirit searches everything, even the depths of God. 11For who knows a person’s thoughts except the spirit of that person, which is in him? So also no one comprehends the thoughts of God except the Spirit of God.
12Now we have received not the spirit of the world, but the Spirit who is from God, that we might understand the things freely given us by God. 13And we impart this in words not taught by human wisdom but taught by the Spirit, interpreting spiritual truths to those who are spiritual.
14The natural person does not accept the things of the Spirit of God, for they are folly to him, and he is not able to understand them because they are spiritually discerned. 15The spiritual person judges all things, but is himself to be judged by no one. 16 "For who has understood the mind of the Lord so as to instruct him?" But we have the mind of Christ.
Do all believers have the Holy Spirit?
Yes.
1 Cor 12:7 Now to each one the manifestation of the Spirit is given for the common good. 8 To one there is given through the Spirit a message of wisdom, to another a message of knowledge by means of the same Spirit, 9 to another faith by the same Spirit, to another gifts of healing by that one Spirit, 10 to another miraculous powers, to another prophecy, to another distinguishing between spirits, to another speaking in different kinds of tongues,[a] and to still another the interpretation of tongues.[b] 11 All these are the work of one and the same Spirit, and he distributes them to each one, just as he determines.
The same Holy Spirit which gives to each of us different gifts to build up Christ’s Church.
Do you believe that one can believe in Jesus and know of His sacrifice without ever having read a line of Scripture?
Do you know that millions and millions of Christians lived and died without ever having read Scripture, studied upon it or interpreted it for themselves?
That includes those who did so before the full canon of Scripture was decided upon by the Church under the guidance of the Holy Spirit.