Proverbs 20:27 tells us, "The spirit of man is the candle of the Lord..." Bod informs our spirit, and our spirit passes the information on to our mind.
The Human spirit has a voice. eE call it guidance, intuition, the inward voice, or conscience. The conscience of an unsaved man is an unsafe guide, because if he has had nay "religious" training, he often will be dominated by it. And if he hasn't, his conscience will permit him to do many things that are wrong.
On the other hand, if a man is born again, his spirit has been made new, with the life and nature of God in it. If his born-again spirit then has the privilege of feeding and meditating on God's Word - if the person practices God's Word, putting it first in his life - then his conscience, the voice of his spirit, will be a safe guide and will become the voice of God speaking to him.
I believe if we walk in fellowship with God through His Word and Prayer, and if we train our spirit through the Word to obey the voice of our spirit instantly, after a while we can know the will of God even in minor details of life.
Jesus said , "And I will pray the Father, and he shall give you another Comforter, that he may abide with you for ever; Even the Spirit of truth; whom the world cannot receive, because it seeth him not, neither knoweth him: but ye know him; for he dwelleth with you, and shall be in you" (John 14: 16-17). Then He said, "Howbeit when he, the Spirit of truth, is come, he will guide you into all truth..." (John 16:13).
I do not believe Jesus was referring here only to the revelation that was to be given to the Apostle Paul concerning God's great plan of redemption. I believe it also means the Spirit of God will guide each of us in the affairs of life.
We should begin our day with the conscious that we have the Holy Spirit as a Guide in us. We were not left without guidance or direction. Jesus said of the Holy Spirit, "He will guide you into all truth...he will shew you things to come" (v.13).
By this Jesus did not mean that the Spirit of God would only show the apostles future events which they recorded in the epistles and the book of Revelation.
Certainly that was a part of it, but I believe this verse also means that the Spirit of God, will show us thing to come in our personal lives. He will show us these things in the future so we can be read for them; we won't be caught unawares.
Excerpt from "The Human Spirit" by Kenneth E. Hagin