A.T. Robertson Commentary Revelation 22:19

"and if any man shall take away from the words of the book of this prophecy, God shall take away his part from the tree of life, and out of the holy city, which are written in this book." — Revelation 22:19 (ASV)

If any man shall take away (εαν τις αφελη). Also condition of the third class with εαν and second aorist active subjunctive of αφαιρεω, with απο repeated both in the condition and in the conclusion (αφελε απο, future active indicative of αφαιρεω for the more usual αφαιρησε).

Which are written in this book (των γεγραμμενων εν τω βιβλιω τουτω). Ablative neuter plural articular perfect passive participle in apposition with εκ του ξυλου της ζωης (from the tree of life) and εκ της πολεως της αγιας (out of the holy city). Such a man is unworthy of his inheritance.