'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)

302. Verse 2. And I saw a strong angel proclaiming with a great voice, signifies exploration by the influx of the Lord into heaven. This is evident from the signification of a "strong angel," as being heaven (of which presently); also from the signification of "proclaiming with a great voice," as being exploration by the influx of the Lord, namely, exploration whether anyone is able to know the states of life of all in heaven and on the earth in general and in particular, for this is what is here treated of. This is signified by "proclaiming," and the influx of the Lord is signified by "a great voice;" for "voice," in reference to the Lord, signifies every truth of the Word, of doctrine, and of faith from Him; and in reference to heaven and the church, it signifies every thought and affection thence; and since everything true and good that angels in heaven and men in whom the church is, think and are affected by, is from the influx of the Lord, this is what is here signified by "a great voice." For it is well known, that no one from the love of good can be affected by good, and from the love of truth can think truth, of himself, but that this flows in from heaven, that is, through heaven from the Lord; and because this is so, "a great voice" signifies the influx of the Lord. (That "voice" in the Word signifies the truth of the Word, of doctrine, and of faith, also everything announced in the Word, see above, n. 261, and Arcana Coelestia 3563, 6971, 8813, 9926; and that it signifies the interior affection of truth and good, and thought therefrom, n. 10454) A "strong angel" signifies heaven because the whole angelic heaven before the Lord is as one man, or as one angel, likewise each society of heaven; therefore by "angel" in the Word an angel is not meant, but an entire angelic society, as by "Michael," "Gabriel," "Raphael." Here, therefore, "a strong angel proclaiming with a great voice" signifies the influx of the Lord into the whole heaven. That it is into the whole heaven is clear from what follows, for it is said, "And no one was able, in heaven nor upon the earth, neither under the earth, to open the book and to look thereon." (That "angels" in the Word mean entire societies of heaven, and in the highest sense the Lord in respect to Divine truth proceeding, see above, n. 90, 130, 200; and that The Whole Heaven before the Lord is as One Man, or as One Angel, and also every Society of Heaven, see in the work on Heaven and Hell 59-87.)