Revelation 4:1,2 - Before me was a door standing open in heaven

4:1

We now enter the main body of Revelation, and John is given a revelation of heaven. In Col 3:2 we are told to set our minds on things above. In order to understand what is happening in the world and, more importantly, how to react to it, we need to have a heavenly perspective. We also need to note that the word heaven is used in various ways, both in the Bible as a whole, and within the book of Revelation. It can mean, as it does here, the dwelling place of God. It can just refer to the heavens in the sense of the sky. It can be the place of spiritual conflict (this is especially the case in Ephesians), it can also be a heaven that is going to pass away, rather than an eternal place. Anyway, here it is the dwelling place of God and is eternal. John is commanded to “come up here”. Some pre-trib rapture proponents see this as being the rapture, but this really is an example of eisegesis, i.e. reading into Scripture what we want to see. “I will show you what must take place”. These events are not best guesses, but are things that must happen. 

4:2

“At once I was in the Spirit”. The Holy Spirit was opening John’s mind to see these things. The first thing he sees is “a throne in heaven with someone sitting on it”. The first thing is that there is a throne. There is a place of ultimate and overall authority. Looking at the world this can seem unlikely at times, but we need to know that this is true if we are to have the right perspective on things. So there is a throne, and there is someone sitting upon it. There is someone who has ultimate authority, and he is exercising that authority.