"A prisonlike, abased condition into which God cast disobedient angels in Noah’s day.
This word is found but once in the inspired Scriptures, at 2 Peter 2:4. The apostle writes: “God did not hold back from punishing the angels that sinned, but, by throwing them into Tartarus, delivered them to pits of dense darkness to be reserved for judgment.” The expression “throwing them into Tartarus” is from the Greek verb tar·ta·ro′o and so includes within itself the word “Tartarus.”
A parallel text is found at Jude 6: “And the angels that did not keep their original position but forsook their own proper dwelling place he has reserved with eternal bonds under dense darkness for the judgment of the great day.” Showing when it was that these angels “forsook their own proper dwelling place,” Peter speaks of “the spirits in prison, who had once been disobedient when the patience of God was waiting in Noah’s days, while the ark was being constructed.” (1Pe 3:19, 20) This directly links the matter to the account at Genesis 6:1-4 concerning “the sons of the true God” who abandoned their heavenly abode to cohabit with women in pre-Flood times and produced children by them, such offspring being designated as Nephilim.—See NEPHILIM; SON(S) OF GOD.
From these texts it is evident that Tartarus is a condition rather than a particular location, inasmuch as Peter, on the one hand, speaks of these disobedient spirits as being in “pits of dense darkness,” while Paul speaks of them as being in “heavenly places” from which they exercise a rule of darkness as wicked spirit forces. (2Pe 2:4; Eph 6:10-12) The dense darkness similarly is not literally a lack of light but results from their being cut off from illumination by God as renegades and outcasts from his family, with only a dark outlook as to their eternal destiny.
Tartarus is, therefore, not the same as the Hebrew Sheol or the Greek Hades, both of which refer to the common earthly grave of mankind. This is evident from the fact that, while the apostle Peter shows that Jesus Christ preached to these “spirits in prison,” he also shows that Jesus did so, not during the three days while buried in Hades (Sheol), but after his resurrection out of Hades.—1Pe 3:18-20."
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