The spirit of man have three main functions
Conscience which discerning right and wrong from knowledge stored in the mind. If you do wrong, you will know it as it is not depending on outside sources.
Intuition is the sensing organ of the spirit. The revelations of God and all info from God is coming through this system. Two elements are critical here: the voice of conscience and the teaching of intuition.
Communion is worshipping God. God can’t be apprehended by our thoughts, feelings or intensions, He can only be known directly by our spirit.
Conscience judges according to intuition. God reveals His will to man in the intuition.
The verses for this three functions is plenty in the Bible.
Unsaved man also have these three functions, but they worship evil spirits. The new Testament does not consider man with a sensitive conscience, keen intuition or a spiritual tendency and interest to be saved. The Holy Spirit is only available to reborn man, not unsaved man. We as Christians know very little about our spirit. Before the believer is born again the spirit is overwhelmed by the soul and has lost his primary function and is dead to God.