In Genesis we have a key to the source behind the knowledge of future events.
The Pharaoh was looking for someone to explain his dreams to him. Here is his conversation.
“And Pharaoh said to Joseph, "I have had a dream, and there is no one who can interpret it. But I have heard it said of you that you can understand a dream, to interpret it." So Joseph answered Pharaoh, saying, "It is not in me; God will give Pharaoh an answer of peace” Genesis 41:15-16 (NKJV).
Joseph was a great man of God. But even he knew he wasn’t the source of the information that he possessed. Only God knows the future.