How does God reveal His truth to us? Muslim believe that is through an angel, but the article tries to reason with them and show them that is done directly as men of God moved by the Spirit. Reasoning from the scripture to show them the errors of their way.
2 Peter 2:1 King James Version (KJV)
But there were false prophets also among the people, even as there shall be false teachers among you, who privily shall bring in damnable heresies, even denying the Lord that bought them, and bring upon themselves swift destruction..