By this reference the angel underscores that vital is not the messenger but the message and hence the obligation that follows from such a message. At this point in time John has not yet shared the revelation with others (per Revelation 1:10), but the assumption is that John will shortly do so. The assumption is further that among those who receive the words of this book
will be those who respond appropriately; that is, they will keep
those words. Those who do so will be in the same league as John and the angel, namely, fellow servants.
9 but he said to me, “You must not do that! I am a fellow servant with you and your brothers the prophets, and with those who keep the words of this book. Worship God.”