Have you ever asked yourself this question when you seem to understand what is going on, and yet is it not something you have been told? Basically, you understand, without being given insight so that you would understand. It is not easy to explain, but I imagine you can follow what I am saying.
For the believer, who has supernatural insight, it points to Holy Spirit. The Spirit of God is telling you something that is outside of your knowledge, and yet you know. Holy Spirit trusts you with a piece of personal knowledge about another person. Very often that other person is a believer, too. However, Holy Spirit can and often will speak of people who are yet to come into the kingdom of God. Remember there are no boundaries or barriers that Holy Spirit cannot cross.
Trust! The Spirit of Truth and Revelation has spoken to you. Do you believe what He is saying, or are you dismissing it as unlikely? Maybe you are not quite in that place of totally believing that God would speak to you. Maybe you have been taught that the extent to which you will hear the voice of God is reading His word. Truthfully, even the words in the Bible will fall short without the Holy Spirit opening them up to your understanding. Spiritual understanding of all things spiritual can only happen through the Holy Spirit.
Holy Spirit brings revelation to believers that points us to the need for relationship, not religion. Religion will only take you so far, but relationship will get you an invitation to walk on the sapphire floor in heaven.
Luke 24:49 Listen carefully: I am sending the Promise of My Father (the Holy Spirit) upon you; but you are to remain in the city (of Jerusalem) until you are clothed (fully equipped) with power from on high.
John 16: 13 But when He, the Spirit of Truth, comes, He will guide you into all the truth (full and complete truth). For He will not speak on His own initiative, but He will speak whatever He hears (from the Father—the message regarding the Son), and He will disclose to you what is to come (in the future).