We read at 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 who are before HIS throne," So who is the "HIM" and who is the "HIS" in this verse? The eternal God.
Verse 5, "and from Jesus Christ, the faithful witness, the first-born of the dead, and the ruler of the kings of the earth. To Him who loves us and released us from our sins by His blood." From this verse it is obviously Jesus Christ.
At verse 6 where He/Jesus Christ has made us to be a kingdom, priests to His God and Father was one of the reasons Jesus incarnated as a man. He not only released us from our sins by His blood, (vs5) but He also (as a man) presented us to His God and His Father.
Verse 7, "Behold, He is coming, with the clouds, and every eye will see Him, even those who pierced Him, and all the tribes of the earth will mourn over Him. Even so, Amen.
Remember, at verse 4, I stated the "Him" is the eternal God. You cannot assume it's the Father because the Father does not qualify as coming in the clouds and because you cannot see the person of God the Father.
Revelation 1:8, "I am the Alpha and the Omega," says the Lord God, who is and who was and who is to come, the Almighty."
Verse 17, "And when I saw Him, (saw who?) I fell at His feet as a dead man. And He laid His right hand upon me, saying, "Do not be afraid, I am the first and the last, vs18, and the living One, and I was dead, and behold, I am alive forevermore, and I have the keys of death and Hades."
Since we know the various text identify Jesus Christ as coming in the clouds, and every eye will see Him (vs8) He must be "God Almighty" and not just a "mighty" god as the Jehovah Witnesses teach. Revelation 22:12-13 also confirms that Jesus Christ is both the Alpha and Omega and the first and the last, the beginning and the end."
The Apostle John closes out the book of Revelation at verses 20, "He who testifies to these things says, "Yes, I am coming quickly." Amen, COME LORD JESUS.
I'm going to add some new information from the jw.org site by quoting the following:
While Jesus Christ is referred to in the previous verse as “coming with the clouds,” the words of Revelation 1:8 and the surrounding verses show that he could not be “the Alpha and the Omega.” In the Scriptures, only the Father of the Lord Jesus Christ is spoken of as “the Lord God” and as the “Almighty.”
Please note in this statement that, only the Father" of the Lord Jesus Christ is spoken of in Revelation 1:8. This is an "assumption" on their part. The word "Father" nowhere appears in Revelation 1:8.
At verse 4 it specifically says, "Grace to you and peace, from HIM who is and who was and is to come." verse 5, and from Jesus Christ etc. As I stated the "HIM" is the eternal God who is God Almighty. I think the following example of what I mean can be explained from Genesis 1:26-27.
Verse 26, "The God said," notice it does not refer to any particular person. It then says, "Let US make man in OUR image." Whatever argument that can be made regarding who the "Us" and the "Our" is really beside the point, why?
Genesis 1:27, "And God created man in "His" own image, in the image of God "He" created him; male and female He created them." In this verse the "His" and the "He" refers to God, and only God, not some specific person.
The same is true at Revelation 1:4, "Grace and peace from "HIM" who is and who was and who is to come; and from the seven Spirits who are before "HIS" throne;" Revelation 4:8-10 identifies the Lord God, the Almighty is on the throne.