For if God spared not the angels— Some think the sense is suspended till we come to 2 Peter 2:9 and the reddition to be looked for there; that is, If God spared not the angels who sinned, &c. the Lord also knoweth how to deliver the godly, &c. This may possibly be the connection; or, if the words ει γαρ are taken affirmatively for since—inasmuch as—there will be no occasion for a reddition afterwards. From this verse to the end of 2 Peter 2:8 are contained three remarkable instances of divine judgments formerly inflicted upon transgressors; which are mentioned by the apostle here in confirmation of what he denounces against those heretics who then infested the Christian churches. The literal translation of the latter clause of this verse is; But confining them in Tartarus, in chains of darkness, he hath delivered them to be reserved unto judgment. The word Ταρταρουν, in St. Peter, is the same as Ριπτειν ες Ταρταρον, to throw into Tartarus, used by Homer; only rectifying the poet's mistake of Tartarus being in the bowels of the earth; and recurring to the true sense of the word, namely, the thick darkness that bounds this created system; which, when applied to spirits, must be interpreted spiritually. And thus the word ταρταρωσας will import, that God cast the apostate angels out of his presence into that blackness of darkness, (Jude 1:13.) where they will be for ever excluded from the glorious light of his countenance. See Parkhurst on the word Ταρταροω.
Related Commentaries of 2 Peter 2:4
2 Peter 2:4
4 For if God spared not the angels that sinned, but cast them down to hell, and delivered them into chains of darkness, to be reserved unto judgment;