1 John 5:9-10

9We believe people who tell us about things that they know. So we can believe even more what God says. He has told us what is true about his Son. So we should believe his message.

10Anyone who believes in Jesus, the Son of God, will know that what God says is true. But anyone who does not believe God is saying that God tells lies. He does not believe the message that God has told us clearly about his Son.