“To show things which must shortly come to pass.” Some endeavor to limit this expression to chapters two and three. But since the same expression occurs in the last chapter of the book it is evident that it must refer to the bulk of the message. “Shortly” can mean nothing else but close at hand or very soon. With all allowance for linguistic flexibility and comparative lengths of periods, it would be stretching language to the breaking point to make shortly mean several thousand years, such interpretations are only trifling with words, and the word of God. The force of these words is decisive. The things that were to be shown in the visions were close at hand; they were to begin with the people to whom the book was written and not thousands of years in the future. God is is own interpreter and must be allowed to say what He means, and what God says in explanation of His own prophecies must be taken in its obvious meaning and regarded as authoritative.
~ David S Clark, The Message From Patmos
