"He who overcomes, I will grant to him to sit down with Me on My throne, as I also overcame and sat down with My Father on His throne" Rev. 3:21.
Sounds to me like they occupy the same throne.
This is a great scripture you have chosen to support the Trinity.
This scripture is analogous to the John 10:30 vs John 17:21 except Rev. 3:21 compresses the thought into 1 scripture.
This is what I mean. John 10:30 says that I and my Father are one. First blush, you would think that is a class A scripture to support the Trinity. How could it be any more clear, Jesus is saying right straight out that he and the Father are one, discussion over.
But then you read a little further in John to John 17 and all of a sudden you start thinking about how this chapter relates to John 10:30, because the verbiage is the same, except that it sounds like that not only are Jesus and God one, but so are the apostles and all that believe in the apostles. That could literally be billions of people that are one with God and Jesus. How can billions of people be in the Trinity?
So we go back to John 10:30 and take another look, especially at the word "one". After careful study and consideration, I came to the conclusion that the word "one" in John 10:30 did not mean that Jesus and God were one physically, but were "one" in mind, will, purpose, and action. They were separate and distinct individuals, but 1 in action "as if they are one God". That was the only solution possible to reconciling John 10 and John 17 and that works. God and Jesus and Holy Spirit in the Godhead working together as 1 and all the rest of us also working together as 1 for the salvation of man.
Now look at Revelations 3:21 in the same way. This portion of Revelations is Jesus talking to the Laodiceans, and he knows their works for good and bad and then tells them of blessings that are open to them if they will overcome the world.
And one of those blessing he offers is in vs 21.
To him that overcometh will I grant to
sit with me in my throne, even as I also overcame, and
am set down with my Father in his throne.
Jesus is indeed set down with his Father in his throne, so at this point it looks like they occupy the same throne. But did you stop to think about how Jesus was going to sit with the Father in his throne, while at the same time sitting with all that overcome the world in his own throne. Sounds to me like there are a lot of people occupying the throne of God. So I have to take a second look at the meaning of this scripture. My solution is that this is a metaphor. All who overcome are not going to really be sitting with Jesus in his throne, that would be a bit difficult, unless Jesus has a great big throne. For the same reason and from the same scripture, Jesus is not really going to sit with the Father in his throne either. We are, however, going to be in the presence of Jesus, around his throne, as he will be in the presence of the Father near his throne.
If this scripture said only that Jesus was sitting with his Father in his throne, then you might have a point. But read and think again about this scripture and you will come to the same conclusion that I have come to.
Again Revelations 3:21 is a good example of how all that overcome and Jesus and God can all work together and be together as "one", even though we are all separate and distinct individuals.