The content of Revelation 22:16 is vital to setting the stage for how one must respond to the revelation Christ has shown to John (including the obligation implicit in Revelation 22:12–13). So Jesus repeats the information initially revealed in Revelation 1:1–3, that the book of Revelation in fact comes from Jesus Christ himself (and behind him from God). This repetition comes hard on the heels of the recent reference to those who love and practice falsehood. Since Revelation comes from Jesus, it is truth (John 14:6).
16 “I, Jesus, have sent my angel to testify to you about these things for the churches. I am the root and the descendant of David, the bright morning star.”