The phrase in question is:
οἱ λοιποὶ τῶν νεκρῶν οὐκ ἔζησαν ἄχρι τελεσθῇ τὰ χίλια ἔτη
The rest of the dead did not come to life until the thousand years were ended.
Metzger's Textual Commentary on the New Testament does not have an entry on this verse, which implies that the committee come to easy consensus on assigning the reading to the "A" category - "certain" (The other categories are B - "almost certain"; C - "the Committee had difficulty in deciding which variant to place in the text"; D - "the Committee had great difficulty in arriving at a decision").
New Testament Manuscript Witnesses
Revelation suffers from a paucity of available manuscripts. Altogether only 15 "witnesses of the first order" are available for the book, 14 "witnesses of the second order", and no "frequently cited witnesses" or "occasionally cited witnesses". By comparison, there are close to 100 witnesses of the first and second order for the Gospel of Matthew.
Further not all witnesses contain Revelation 20:5. Of the witnesses of first order, only four manuscripts contain the verse:
- Codex Sinaiticus - c. 330-360; origin St. Catherine's Monastery, Sinai
- Codex Alexandrinus - c. 400-440; origin uncertain, probably Egypt
- Codex Ephraimi - 6th c.; probably Egyptian origin, brought to Florence after the fall of Constantinople in 1453
- Codex Athous Pantokratoros - aka "Uncial 051" - 10th c.; currently at Mt. Athos Greece, where it likely was first transcribed
The committee also considers the majority reading in all available manuscripts (witnesses of first and second order, in the case of Revelation) as itself comprising a witness of first order.
Andrew of Caesarea
The manuscript corpus for Revelation is also unique in that a significant witness for the book is the large collection of manuscripts - over 80 - of the commentary of Andrew of Caesarea, an eastern hierarch who lived in the 7th and 8th century.*. The Nestle-Aland committee assigned the majority reading of the encapsulated Revelation text in Andrew's commentaries to the group of witnesses of first order.
Weight for Inclusion
Of the six witnesses of first order that contain Revelation 20:5, three are with the phrase and three without. With the phrase are:
- Codex Alexandrinus (early 5th c.)
- Codex Athous Pantokratoros (10th c.)
- The majority of manuscripts containing the commentary of Andrew of Caesarea
Without the phrase are:
- Codex Sinaiticus (early to mid 4th c.)
- Codex Ephraimi (6th c.)
- Majority of witnesses of second order
In addition, the phrase appears in the majority of early Latin manuscripts, but not in Syriac or Coptic.
* See E. Constantinou, Andrew of Caesarea and the Apocalypse in the Ancient Church of the East