'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.

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

129. Anybody can recognize that the basic assumptions a person makes, even when completely false, govern him, and that all knowledge and reasoning buttress those assumptions. For countless flattering ideas occur to him to confirm him in falsities. Consequently when a person's basic assumption is to believe nothing until he sees and understands it, he cannot possibly believe; for spiritual and celestial things are neither visible to the eyes nor comprehensible in mental images. But the true order is for a person to become wise from the Lord, that is, from His Word. In that case everything follows as it should, and he is also enlightened in matters of reason and of fact. Indeed nobody is forbidden to acquire knowledge, since it is useful for life and gives delight. And the person in whom faith resides is in no way forbidden to think and to talk as learned people in the world do. But he does so from the premise of belief in the Lord's Word and of confirming spiritual and celestial truths by means of natural truths, using as far as is possible the terminology of the learned world. Consequently his premise must be the Lord, not self; the former is life, while the latter is death.