So what do you think LIVING WATERS flow into... literal seas? Remember the new testament already told us that the living waters are the Holy Ghost.
This is how rightly dividing the word of truth works. The division isn't discerning between Israel and the church, the division is between the spritual and the literal.
Reading the bible and "spritualizing" things isn't rightly dividing, we can't say this symbolizes that because I think it does, it has to be concrete evidence. In the case of the living water we are told that living water is the Holy Ghost. We can't change the meaning of the definition just because it's in the book of Revelation or it doesn't fit what we THINK we know.
If the living waters are flowing into a sea, then it's not a literal sea. It HAS to be something that the Holy Ghost can flow into. It can only be two things that I can think of, people or the word.
The bible is symbolized as water, so it makes sense that the FORMER sea would be the Old Testament and the HINDER or LAST sea would be the last or new testament. OR it could be talking about saved Jews of the FORMER testament and Gentiles of the LAST testament... people are symbolized as people in the bible also - "many waters"
I thinks its talking about the old and new testament BUT it doesn't matter as far as understanding the time stamp that it places on Zechariah 14:8... LIVING WATERS flowed out of Jerusalem when Jesus came the FIRST time.
Zechariah 14:8 KJV
And it shall be in that day, that living waters shall go out from Jerusalem; half of them toward the former sea, and half of them toward the hinder sea: in summer and in winter shall it be.