Old Church Slavonic - Revelation 16:5

The OCS Apocalypse apparently goes back to Methodius' translation in 885 (link to source), however the oldest manuscripts may only be from the 14th century (link to source).

I was able to find a printed OCS text beautifully typeset, which had the following text:

(p. 2683/2696)

My own translation is this:

And I heard the angel of the waters say: righteous you are, O Lord, [the] being [one] and which was, and holy, because thus judged you:

(both instances of "you" are singular) 

A corresponding transliteration of the OCS to modern Russian (Cyrillic) letters is this:

  

И слышах Ангела воднаго глаголюща: праведен еси, Господи, сый и Иже бе, и преподобн, яко сия судил еси: (source)(Step Bible offers here as the 1757 Church Slavonic Elizabeth Bible)

The word "преподобн" is an OCS word used to translate hosios. So, in terms of being an additional confirmation of the pre-Bezean form of the text, the OCS seems to be fairly mainstream.  Unfortunately, however, I do not know how critical this printed text is, and whether, as Metzger (p. 430) suggests, it was influenced by Latin at an early (9th or 10th century) stage.  It is even possible that the printed OCS text I located was amended to align with an early printed Greek text.      

H.T. "Base form dictionary"

H.T. Slavonic Titlo

H.T. Slavonic conjugation of "to be"

H.T. Dictionary of the Oldest Old Church Slavonic Manuscripts:

прѣподобьнѣ

прѣподобьнъ

правьдьнъ