Revelation, Apocalypse does not speak of sipirit of prophecy but of spirit of THE prophecy that is the book of Revelation.
It seems that Only the ABP (The Apostolic Bible Polyglot 2006) version PERFECTLY translates Revelation 19:10.
Revelation 19:10 ABP
(10) And I fell before his feet to do obeisance to him. And he says to me, See that you do not! [fellow-servant I am your], and of your brethren having the testimony of Jesus; to God do obeisance! For the testimony of Jesus is the spirit of the prophecy.