'The first resurrection,' mentioned in Revelation 20:5, 6, does not mean a first resurrection, but the essence and primary part of resurrection, which is salvation and eternal life. There is only one resurrection to life. A second does not happen, and is not mentioned anywhere in the Bible.

(References: Apocalypse Explained 6; Apocalypse Revealed 851; Revelation 20:5-6)

300. Sealed up with seven seals, signifies altogether hidden, namely, the state of life of all in heaven and on the earth. This is evident from the signification of "sealed with seals," as being to be hidden, for what is contained in a book sealed up with seals no one knows until it is opened and read; also from the signification of "seven," as being all persons and all things, also what is full and entire (See above, n. 257); thus also altogether, because this means fully and wholly.