When we believe in the Lord Jesus Christ, we are born again. The Holy Spirit comes into our lives and regenerates our spirit. We become children of God. The Holy Spirit abides in us and helps our spirit grow inside us. The work of the Holy Spirit with our spirit in us is deep and supernatural. It is not intelligible to our mind because our mind has been so affected by sin, the flesh and the world. If we want to understand the work of the Holy Spirit inside us, we must renew our mind.
Our mind is part of our soul which is the meeting point of the physical realm and the spiritual realm. Our mind can be influenced by the world outside through our body or by the Holy Spirit inside through our spirit. Our mind has been so influenced and conformed to the world outside that it does not understand and even reject the work of the Holy Spirit inside. If we don’t do something about this, the Holy Spirit will not be able to transform our lives because He and our spirit will be confined inside.
The transformation of our lives is only possible when we renew our mind according to the mind of God. The Holy Spirit reveals the mind of God to our mind from our spirit supernaturally, but because our mind is still being influenced by the world through our body, the complete renewal of our mind is impossible until we replace that influence with something which is in line with the Holy Spirit inside. That something is the Bible because the Bible is the only revelation of the mind of God available in the world.