Paul in his Letter to the Corinthians speaks of the gift of discernment:
To each individual the manifestation of the Spirit is given for some benefit. To one is given through the Spirit the expression of wisdom… to another prophecy; to another discernment of spirits…
What is the gift of discernment of Spirits? It comes in different forms, four of which I will elaborate upon. First, the gift of discerning God’s will for one’s self is a gift of the Holy Spirit. This gift is the ability to know and to act upon the particular vocation we have, and to act in accord with God’s will on a regular basis. The gift of discernment is a spiritual gift unrelated to education. Jesus demonstrated the gift of discernment, and obedience, in the Garden of Gethsemene when he said, Father, if you are willing, take this cup away from me; still, not my will but yours be done. (Luke 22: 42)
Second, a different type gift of discernment of Spirit can speak to a person’s ability to intuit the spiritual condition of others. The Apostle Peter demonstrates this gift in the Acts of the Apostles, when he challenges the insincere gift of Ananias in Acts 5: 3-4: Ananias, why has Satan filled your heart so that you lied to the Holy Spirit and retained part of the price of the land?… You have lied not to human beings, but to God.
A third class of this gift allows us to discern truth from falsehood. This gift allows us to know when someone is deceiving us for reasons that might result in our spiritual harm. On the other hand, it also allows us to recognize the truth immediately, without any experiential knowledge of it. This gift has nothing to do with street smarts, book knowledge, or people-reading skills. It is not a sixth sense, but rather a gift of the Holy Spirit. John the Baptist demonstrates this gift in John 1: 15-17, This was he of whom I said, ‘The one who is coming after me ranks ahead of me because he existed before me… ” because while the law was given through Moses, grace and truth came through Jesus Christ.
A fourth gift of discernment of Spirits allows us to actually have knowledge of a supernatural or preternatural reality. Consider what Jesus told the disciples regarding what they could accomplish through faith in Mark 16: 17, These signs will accompany those who believe: in my name they will drive out demons, they will speak new languages. Being able to successfully perform a “deliverance” or an “exorcism” is a charism or gift in itself, but it requires the ability to discern Spirits. One cannot expel a demon if one cannot discern its presence or absence.