I want to share with you what I think the main symbols of Revelation mean, because I haven't really heard anyone preaching it like that. There is nothing harsh ethically or otherwise in it. Please comment on what you think, and whether you think it fits with the rest of the Bible.
Basically, I think that when it says "buy and sell" in chapter 13, it means to teach teachings that are untrue, just as in the Prophets a prophet mentioned buying wine and milk "for free" in the sense of receiving true teachings, the truth here being God -- the only uncreated being in existence, while everything is something created.
And just as for 6 days God created everything, so also all creation can be symbolized by a six, while He Himself -- by a seven -- the eternal Day for rest, the eternal Sabbath. And so, all the "created truth", can be represented by a six.
And in the end times, whoever will receive a false teaching, and believe it, would receive the spirit of faith in something created yet not true. While the true believers would continue to have the Holy Spirit of faith in things that are true (Spirit is the spirit of faith in truth).
And this is where the Revelation mentions image of the beast. Image is something worshipped. And if the image speaks, it means it's a human being, or the words of this human being, which are received by people instead of the words of Christ. These other words can't find justification in the Bible that is.
But not only the teaching of people can be something created -- our goods deeds can be too. They are after all the creations of our hands, even though they come with the help of God. And so they cannot be worshipped either, aka believed in for salvation. I.e. we do them knowing they save because of Matthew 25, yet after we worked them, we don't remember them and don't trust in them as the foolish farmer in his crop. We forget them like the right hand mustn't know what the left hand does, and we just say: we did what we had to, we are unprofitable slaves of God. The danger from these works come because they don't have eyes to see or ears to hear, and so trusting in them for salvation would seem to only make God angry -- provided God is the same God as He was in the Old Testament.
So what are we left with, is to only believe for salvation in the presence of the Holy Spirit in us, which *is* the Blood of Jesus, because the "blood of every creature is its life", yet the Spirit is Eternal Life -- "my Words are Spirit and they are Life". When our heart has the Holy Spirit, the inner, shabby, sin-nature-ridden garments of our heart are made clean. Yet if guilty conscience shipwrecks our faith, the wine of the Spirit flows out through the holes, burnt by these hot coals (a seared conscience just doesn't feel them, yet the effect on our wine sack is the same). And we become naked, and our shame can be seen -- the Wedding Garment gone. Yet, if we have not trusted in our grapes for salvation (meaning the works of Matthew 25) and haven't been lucky to go the Lord with the oil of the Spirit filling to the brim the lamp of heart, these grapes will provide the last washing of the Blood of Jesus at the Great Judgement ("the blood of grapes"). But if we do die in the Lord, we go to heaven right away, as it's written (I'm paraphrasing): they who have the Spirit of faith to the brim, because of the wine sack without holes and works of praise to the Lord, shall not come to the Judgment, but have already passed from death to life.