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Jude 12 These are spots in your feasts of charity, when they feast with you, feeding themselves without fear: clouds they are without water, carried about of winds; trees whose fruit withereth, without fruit, twice dead, plucked up by the roots;
Using Strong’s Concordance: twice (Strong’s dictionary number 1364) from 1417 which is duo meaning two - adverb
Translated in the Authorised Version as "twice” 4 times, and "again” 2 times.
Mark 14:30 And Jesus saith unto him, Verily I say unto thee, That this day, even in this night, before the cock crow twice <1364>, thou shalt deny me thrice.
Mark 14:72 And the second time the cock crew. And Peter called to mind the word that Jesus said unto him, Before the cock crow twice <1364>, thou shalt deny me thrice. And when he thought thereon, he wept.
Luke 18:12 I fast twice <1364> in the week, I give tithes of all that I possess.
Philippians 4:16 For even in Thessalonica ye sent once and again <1364> unto my necessity.
1 Thessalonians 2:18 Wherefore we would have come unto you, even I Paul, once and again <1364>; but Satan hindered us.
They had once been dead in trespasses and sins.
Ephesians 2:1 And you hath he quickened, who were dead in trespasses and sins;
Had been baptised into Christ and been rescued from sin and death.
Ephesians 2:5 Even when we were dead in sins, hath quickened us together with Christ, (by grace ye are saved;)
And subsequently fallen away and lapsed back into their former state.
Hebrews 10:26 For if we sin wilfully after that we have received the knowledge of the truth, there remaineth no more sacrifice for sins,
They were then dead again (for the second time) and will be subject to resurrection, judgment and the second death.
Revelation 21:8 But the fearful, and unbelieving, and the abominable, and murderers, and whoremongers, and sorcerers, and idolaters, and all liars, shall have their part in the lake which burneth with fire and brimstone: which is the second death.
The ‘lake of fire and brimstone’ is not to be understood as eternal torment but as a symbol of utter destruction representing the second death.
I hope this helps.