I was in the Spirit
Once again, John was in the Spirit, as he was at the beginning of his vision (Rev. Rev. 1:10+). Ezekiel described his similar experience as the hand of the Lord being upon him (Eze. Eze. 1:3; Eze. 3:14). Later, he records: the Spirit lifted me up between earth and heaven, and brought me in visions of God to Jerusalem (Eze. Eze. 8:3). In subsequent visions, the Spirit took Ezekiel to Chaldea (Eze. Eze. 11:24) and to the valley of dry bones (Eze. Eze. 37:1). Paul was caught up to the third heaven in a similar experience, although he does not mention the Spirits involvement (2Cor. 2Cor. 12:1-2). Being in the Spirit refers not only to spiritual or physical transport to a new location or vantage point, but to a unique empowerment by the Spirit to receive special revelatory communication from God (Eze. Eze. 2:2; Eze. 3:12-14; Gal. Gal. 1:16; Gal. 2:2; Eph. Eph. 3:3). Although the text does not explicitly say so, John was probably transported to heaven. The command was for him to come up here. The Spirit transports John to the wilderness (Rev. Rev. 17:2+) and a great and high mountain (Rev. Rev. 21:10+) later in the book.
One sat on the throne
Prior to being given great revelation, prophets are often exposed to the glory of God. Earlier, John saw the glorified Jesus. Now he will be shown the throne room in heaven. Isaiah had a similar vision of God on His throne (Isa. Isa. 6:1). This is where Jesus is presented to the Ancient of Days to receive His kingdom (Dan. Dan. 7:9-14). In Ezekiels vision, on the likeness of a throne was a likeness with the appearance of a man (Eze. Eze. 1:26). Isaiah also saw Him: I saw the Lord sitting on a throne, high and lifted up, and the train of His robe filled the temple (Isa. Isa. 6:1).
See commentary on Revelation 1:12.
The One sitting is God the Father, not Christ, for Christ comes to the One on the throne to receive the scroll with the seven seals (Rev. Rev. 5:1-7+). This is the One whose wrath, along with that of the Lamb, is poured out upon the earth dwellers (Rev. Rev. 6:16-17+) and to Whom, along with the Lamb, salvation belongs (Rev. Rev. 7:10+).
He is sitting on the throne which emphasizes His ultimate rule and control of all that transpires in the book (Rev. Rev. 4:5+, Rev. 4:9+, Rev. 4:10+; Rev. 5:1+, Rev. 5:6+, Rev. 5:7+, Rev. 5:13+; Rev. 6:16+. Rev. 7:10+, Rev. 7:15+; Rev. 16:17+; Rev. 19:4+; Rev. 20:11-15+; Rev. 21:5+). Even the final manifestation of evil is dependent upon permission being granted from the Father (Rev. Rev. 3:21+; Rev. 6:4+; Rev. 7:2+; Rev. 13:7+, Rev. 13:14+, Rev. 13:15+). God is completely sovereign over the affairs of history, yet those who participate in sin are fully responsible moral agents (Acts Acts 2:22-23). Gods throne is prominent throughout the book and indicates His ultimate role as judge (Rev. Rev. 20:11+).1
Hundreds of years before John, Ezekiel saw the same One seated on His chariot throne:
And above the firmament over their heads was the likeness of a throne, in appearance like a sapphire stone; on the likeness of the throne was a likeness with the appearance of a man high above it. Also from the appearance of His waist and upward I saw, as it were, the color of amber with the appearance of fire all around within it; and from the appearance of His waist and downward I saw, as it were, the appearance of fire with brightness all around. Like the appearance of a rainbow in a cloud on a rainy day, so was the appearance of the brightness all around it. This was the appearance of the likeness of the glory of the LORD. So when I saw it, I fell on my face, and I heard a voice of One speaking. (Eze. Eze. 1:26-28)Ezekiel was overcome by what he saw. Here, no mention is made of John collapsing under the vision of Gods glory as occurs so frequently elsewhere (Isa. Isa. 6:5; Eze. Eze. 1:28; Eze. 3:23; Dan. Dan. 10:8; Mtt. Mat. 17:6; Mark Mark 9:6; Acts Acts 9:4; Rev. Rev. 1:17+). Perhaps this is because John had already been strengthened by Christ following his collapse at the earlier revelation of the risen Christ (Rev. Rev. 1:17+).
What John sees is not some immaterial spiritual revelation, but a real material place:
Heaven is a material place. John saw a throne. If the objection is that he was in the Spirit and that it might be a spiritual throne, we would answer that the body of Jesus Christ was raised from the dead and that our Lord said, Handle me, and see; for a spirit hath not flesh and bones, as ye see me have (Luke Luke 24:39); and it was that body which ascended into Heaven. There must be a material Heaven or there was no ascension, and if there was no ascension, there was no resurrection, and if there was no resurrection, there is no salvation.2
1 Gods throne appears in Rev. Rev. 1:4+; Rev. 3:21+; Rev. 4:2-6+, Rev. 4:9-10+; Rev. 5:1+, Rev. 5:6-7+, Rev. 5:11+, Rev. 5:13+; Rev. 6:16+; Rev. 7:9-11+, Rev. 7:15+, Rev. 7:17+; Rev. 8:3+; Rev. 12:5+; Rev. 13:2+; Rev. 14:3+, Rev. 14:5+; Rev. 16:10+, Rev. 16:17+; Rev. 19:4-5+; Rev. 20:11+; Rev. 21:5+; Rev. 22:1+, Rev. 22:3+.