For the third time in very short order we’re told that someone spoke. The first-person pronouns in Revelation 21:6–7 suggest that the speaker remains God, the one was seated upon the throne (Revelation 21:5). The addition of the words “and he said to me” indicates that the words now being spoken need not be written down with the same urgency as the words of Revelation 21:5b (though of course they must also be written down in keeping with the command of Revelation 1:11, Revelation 1:19).
6 And he said to me, “It is done! I am the Alpha and the Omega, the beginning and the end. To the thirsty I will give from the spring of the water of life without payment.