The testimony of Jesus is the spirit of prophecy

[Peairtach]

And he saith unto me, Write, Blessed are they which are called unto the marriage supper of the Lamb. And he saith unto me, These are the true sayings of God.

And I fell at his feet to worship him. And he said unto me, See thou do it not: I am thy fellowservant, and of thy brethren that have the testimony of Jesus: worship God: for the testimony of Jesus is the spirit of prophecy
(Rev. 19:9-10, KJV)

What does "the testimony of Jesus is the spirit of prophecy" mean?

 

[Contra_Mundum]

I think he means to convey to John that they are alike (even though the angel is glorious), in that they both have a common portion of the same Spirit--the same Spirit gives each of them the same witness to Jesus--who is God to be worshiped.

 

[Peairtach]

It's not (also) about the fact that "prophecy" was going to be superseded by "the testimony of Jesus"? The latter wouldn't by itself explain the word "for".

 

[Contra_Mundum]

I believe the explanatory gloss means you can interchange the latter phrase for the former in the primary clause, and the meaning is basically the same. Thus, enriching the original thought.