Revelation 1:4

John to the seven churches that are in Asia: Grace to you and peace, from him who is and who was and who is to come; and from the seven Spirits that are before his throne.

To the seven churches ... It is evidently John's preference for the number seven that lies behind this book's being directed to only seven congregations, because the New Testament names others in the same province, namely, Troas, Colossae and Hierapolis. Among the Hebrews, this was a sacred number often used to symbolize the whole or the completeness of something. Thus, the interpretation of these seven standing for all of the congregations of Christ throughout the world would appear to be correct. "It is certain that while the book is addressed to a limited circle of Asian churches, the author's purpose was to reach beyond these to all the churches throughout the world."[9] The evidence of this universal destination of the book is found in the repeated injunction, "He that hath an ear, let him hear what the Spirit saith to the churches."

Of Asia ... In the New Testament, Asia always means the Roman province located in the western part of what is now known as Asia Minor, with a possibly wider meaning in Acts 2:9.

Grace to you and peace ... Greetings similar to these are found in nearly all the New Testament epistles, especially those of Paul.

From him who is and who was and who is to come ... The Greek words from which this is translated are literally, "The BEING and the WAS and the COMING."[10] Of course, in English this is not grammatical, nor for that matter is it grammatical in the Greek; but as Moffatt said, "(This is) a deliberate violation of grammar to preserve the immutability and absoluteness of the divine name."[11] There are many examples of such awkward grammar in this prophecy; but "(They) are not due to ignorance of Greek construction, as shown by the predominantly correct uses in the book."[12] This title of God is essentially that of Exodus 3:14, "I AM who I AM." Christ also used this title of himself in Mark 6:50; Mark 13:6; Mark 14:62, and in John 6:35; John 8:12; John 10:7; John 11:25 and John 14:6.

And from the seven Spirits that are before his throne ...; Isaiah 11:2 has this:

And the spirit of the Lord shall rest upon him, the spirit of wisdom and understanding, the spirit of counsel and might, the spirit of knowledge and of the fear of the Lord.

There are seven titles of the Holy Spirit in this passage from Isaiah, and from very early times this reference in Revelation has been associated with it. "It denotes the Holy Spirit in the plenitude of his grace and power."[13] The decisive reason for this interpretation was given by Hinds: "It is used in the salutation in direct association with God and Christ, and a blessing is invoked from the three."[14]