Is it "literal"? Yes, I'd say everything we read actually happened/happens. John didn't imagine it. Within that context, were the literal things he experienced spiritual or physical? Well, I'd say most were spiritual (with exception)...and if spiritual, they're not going to play out the same way for our eyes in the physical. The physical fulfillment will look different than what's described in the spiritual. But there will always be signs or markers to match up the physical event with the spiritual description...but it all literally happens.
For example, Daniel saw four beasts in his vision. Similarly to John, he was also meditating
in the spirit. The angel tells Daniel that these four beasts are four actual kingdoms (empires). We know that the one beast that looked like a lion with wings represented the Babylonian empire because the physical banner of the empire was a winged lion matching this spiritual vision.
Another example, Scripture explains that each kingdom/nation has a Principality (i.e., Archangel) that presides over it. Recall at another time that the angel Gabriel couldn't get to Daniel to explain a vision he had because he was resisted/prevented by the Princ(ipality) of Persia until he received help from Michael, the Princ(ipality) of Israel. In the physical, recall that the Persians took the Israelites captive after they conquered the Babylonians. Daniel had to deal with challenges like the lion's den, so you can imagine that being strong in God (Gabriel) during that time of tribulation was difficult. The spiritual is the true object, while its physical representation in our world is the shadow that the object casts in the presence of Light (The Almighty).
So in truth, the Babylonian kingdom was literally a winged lion in the spirit, but physically was what our historical records describe it looking like and having. So likewise, when we read of the four horsemen being sent out from heaven, those are truly spirits being sent out. But what do they look like in the physical? Actual wars and confrontations between nations, extreme poverty and hunger, strange diseases, followed by plagues & death.
[This is why I believe that a lot of the book has already happened physically in our world, especially in the case of the four horsemen. Humanity has suffered through 2 terrible world wars (with a 3rd one possibly triggered last weekend), poverty, plagues, and death since the first century. There isn't much left by my estimation.]
For another example, we see a seven-headed dragon in the sky, ready to devour the manchild that the woman with a crown of twelve stars will bear. If we follow the rules established in scripture for interpreting these spiritual visions, this is a summary of satan preparing to kill the messiah once He is born. But when He is taken to heaven, a war breaks out in heaven and satan is cast to earth, where he pursues and persecutes the descendants of Israel in revenge.
We know the first part of this physically happened in the gospels, as King Herod attempted to kill Christ when he was born. But the second part had a national/kingdom fulfillment because just like the Babylonian empire used the winged lion for its banner, the banner of the pagan Roman army was the draco (i.e., the dragon). Meanwhile, the nation of Israel was always called The Almighty's woman or wife in the scriptures, with 12 stars representing the 12 tribes. We know that Christ ascended in the first century, and history testifies to the constant persecution of the Israelites at the hands of Rome after Christ's ascension, which means satan has been kicked out of heaven for nearly 2000 years.
The book continues, saying a flood came out of the dragon's mouth to drown the woman, but the earth swallowed up the flood.
Daniel 9:26 explains that Jerusalem will be destroyed by the army of the prince, "like a flood". So the spiritual flood is a physical army. History records that the army of pagan Rome wiped out Jerusalem like a tsunami and continued to persecute the Jews until invaders began attacking Rome and draining its strength, leading the empire to break into multiple nations (this was the physical fulfillment of the earth spiritually swallowing up the flood and becoming a sea).
Next in Rev 13, we read that a beast rises from that sea looking exactly like the dragon (with 7 heads), and the dragon gives his authority to the beast to persecute the saints as all the world marvels at the beast while it speaks blasphemies. Building on what we know, a beast is a kingdom. So this kingdom rose from the fall of pagan Rome, looking exactly like Rome. Pagan Rome gave its authority to this kingdom, and this kingdom began speaking blasphemies. History records that the Roman emperor gave authority to the bishop of Rome (i.e., the pope), and when Rome fell, the Holy Roman Empire rose to power with the Papacy (said to represent God in the flesh, called "Vicar of Christ") as its head. All the kings of the known world bowed to the pope while he passed religious policies that persecuted the Jews throughout the Middle Ages. He is also the one who authorized the
Holy Wars, Inquisitions of "protestants", and slavery of "heretics" who did not convert to Roman catholicism, initiating the transatlantic
slave trade.
"He that goes into captivity, into captivity he will go. He that is killed with the sword, with the sword he will be killed. This is the patience of the saints."
The Pope's persecution continued from 538 AD to 1798 AD (1,260 physical years = 42 spiritual months), when the French ended the papacy. At the same time, another beast was emerging from the earth, which would assume the world-leading power of the first beast. What empire was born in a sparse land around the same time the papacy was ended (in the late 1700s)? Appearing innocent like a lamb, with two horns of authority, but speaking like a dragon? Who developed the power to call fire down from heaven (Heaven = Uranos = Uranium)? Who developed the power to give life to the image (i.e., life to the image = animate the image = motion pictures)? Causing all who will not worship the beast
should be killed (i.e., propagandizes through media to make enemies of the non-compliant)...
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So literal, but spiritual...and it's on us to match it up with the physical using the rules established in scripture.