The three witnesses
witness 1-the life of Jesus, particularly His baptism, where God Himself spoke, “This my beloved Son,” (Your victory is bound up in your Identity).
witness 2-the death of Jesus; John refers to this as the testimony of blood. That's why the book of Acts can refer to “the blood of God.”
witness 3-the resurrection of Jesus; John refers to this as the testimony of the Spirit. Because of the resurrection, God sent His Spirit so that each of us, as we believe, say “I’m changed.”