That's a good question. Unfortunately, if you ask someone, they will instinctively tell you that they are listening to the Holy Spirit. This is why John admonishes: "Beloved, believe not every spirit, but try the spirits whether they are of God: because many false prophets are gone out into the world." 1 John 4:1. When one has the Holy Spirit, they already know what they must do to try the spirits to see if they are of God.