Textual Variants
πᾶς γὰρ πυρὶ ἁλισθήσεται καὶ πᾶσα θυσία ἀλὶ ἁλισθήσεται TR, 1550
πᾶς γὰρ πυρὶ ἁλισθήσεται NA28
According to Constantin Tischendorf’s critical apparatus,

The following exegesis is based on the lengthier variant.
Exegesis of Mark 9:49
- The conjunction γὰρ (“for”)
The conjunction γὰρ connects Mark 9:49 with the preceding verses; therefore, Mark 9:49 must be interpreted with those same verses in mind.
In The Greek New Testament, Henry Alford wrote,1
What is γάρ? It connects it with the solemn assertions in Mark 9:43-48, καλόν ἐστίν σε... (It is better for you...) and furnishes a reason why it is better for us to cut off and cast away, &c.
Exegesis of Mark 9:43-48
43 And if your hand offend you, cut it off. It is better for you to enter the life crippled rather than having two hands to go into Gehenna, into the unquenchable fire. 44 where their worm does not die, and the fire is not quenched. 45 And if your foot offend you, cut it off. It is better for you to enter the life crippled rather than having two feet to be cast into Gehenna, into the unquenchable fire. 46 where their worm does not die, and the fire is not quenched. 47 And if your eye offend you, pluck it out. It is better for you to enter the kingdom of God one-eyed rather than having two eyes to be cast into the fiery Gehenna, 48 where their worm does not die and the fire is not quenched.
43 Καὶ ἐὰν σκανδαλίζῃ σε ἡ χείρ σου ἀπόκοψον αὐτήν καλόν σοι ἐστίν κυλλὸν εἰς τὴν ζωὴν εἰσελθεῖν ἢ τὰς δύο χεῖρας ἔχοντα ἀπελθεῖν εἰς τὴν γέενναν εἰς τὸ πῦρ τὸ ἄσβεστον 44 ὅπου ὁ σκώληξ αὐτῶν οὐ τελευτᾷ καὶ τὸ πῦρ οὐ σβέννυται 45 καὶ ἐὰν ὁ πούς σου σκανδαλίζῃ σε ἀπόκοψον αὐτόν καλόν ἐστίν σοι εἰσελθεῖν εἰς τὴν ζωὴν χωλὸν ἢ τοὺς δύο πόδας ἔχοντα βληθῆναι εἰς τὴν γέενναν εἰς τὸ πῦρ τὸ ἄσβεστον 46 ὅπου ὁ σκώληξ αὐτῶν οὐ τελευτᾷ καὶ τὸ πῦρ οὐ σβέννυται 47 καὶ ἐὰν ὁ ὀφθαλμός σου σκανδαλίζῃ σε ἔκβαλε αὐτόν καλόν σοι ἐστιν μονόφθαλμον εἰσελθεῖν εἰς τὴν βασιλείαν τοῦ θεοῦ ἢ δύο ὀφθαλμοὺς ἔχοντα βληθῆναι εἰς τὴν γέενναν τοῦ πυρὸς 48 ὅπου ὁ σκώληξ αὐτῶν οὐ τελευτᾷ καὶ τὸ πῦρ οὐ σβέννυται
The Lord Jesus Christ repeately refers to Gehenna (γέεννα), the place of eternal punishment which Christianity often refers to in English by the proper name “Hell.” So severe and so abhorrent is the place and the punishment therein that he implores his listeners in this life to cut off their hand or foot, or pluck out their eye, if these body parts would cause them to sin and warrant the judgment/punishment of Gehenna.2 In Gehenna, which he describes by the attributive genitive τοῦ πυρὸς as “fiery,” there is unquenchable fire (τὸ πῦρ τὸ ἄσβεστον). Although this same name referred to a dump in the valley of Hinnom (pictured below), also known as Tofet (תֹּפֶת), it was later associated with the place of the eternal punishment of the wicked in the world to come.

In his commentary on Psa. 27:13, David Kimchi wrote,3
And I believed that I had hope in Yahveh and would see His goodness in the world to come. And this is “in the land of the living” (בארץ חיים). And he called the world to come “the land of the living.” And although the soul has no place or any dwelling on earth, yet as the goodness of the world to come is compared to Gan Eden, which is (literally) a place on earth, it was said by way of a parable for the understanding of the hearers.
האמנתי שיש לי תקוה בח”י ואראה בטובו לעולם הבא. וזהו בארץ חיים. וקרא לעולם הבא ארץ חיים, ואף על פי שאין לנשמה מקום וכל שכן ארץ. אלא לפי שנמשל טוב עולם הבא לגן עדן, שהוא מקום בארץ, להבין השומעים נאמר דרך משל.
Likewise, the judgment of the wicked is called “Gehinnam.” And it is (literally) a place on earth near Jerusalem. And it is a repulsive place, and they throw unclean things and corpses there, and there was always fire there to burn the unclean things and the bones of the corpses. Therefore, the judgment of the wicked is called “Gehinnam” (גיהנם) by way of a parable. And the reward of the righteous is called “Gan Eden,” which is the most remarkable place on earth, and it is called “the land of the living” since when a man is expelled from there, he is sentenced to death.
כמו שנקרא גם כן משפט הרשעים גיהנם והוא מקום בארץ סמוך לירושלים, והוא מקום נמאס ומשליכים שם הטומאות והנבילות, והיה שם אש תמיד לשרוף הטומאות ועצמות הנבילות, לפיכך נקרא על דרך משל משפט הרשעים גיהנם. ונקרא שכר הצדיקים גן עדן, שהוא מקום המשובח בארץ והוא נקרא ארץ חיים, כי כאשר גורש האדם משם נקנסה עליו מיתה.
- πᾶς...πυρὶ ἁλισθήσεται (“all/every one shall be salted with fire”)
Commentaries differ on their understanding of the word πᾶς, meaning “all.” For example, in Horae Hebraicae et Talmudicae, John Lightfoot wrote,4
πᾶς, all, is not to be understood of every man, but of every one of them "whose worm dieth not," &c.
However, in The Greek New Testament,5 Henry Alford wrote,
πᾶς then is every one, absolutely: referring back both to the σε, and the αὐτῶν above.
In other words, “everyone shall be salted with fire” must refer to, not only the preceding σε (“you”) in v. 43, 45, and 47 where the Lord Jesus Christ implores his audience to cut off their hand, foot, or pluck out their eye if any of those body parts “offend you” (σκανδαλίζῃ σε) — these people undoubtedly being righteous — but also to αὐτῶν (“their”) which refers to the unrighteous whose worm does not die in v. 44, 46, and 48.
Alford further remarked,6
πᾶσα θυσία (“every sacrifice”) is...parallel with πᾶς, and καί equivalent to just as.
In other words, πᾶς πυρὶ ἁλισθήσεται (“everyone shall be salted with fire”) is equivalent to πᾶσα θυσία ἀλὶ ἁλισθήσεται (“every sacrifice shall be salted with salt”).
If Alford is correct in that the two clauses are parallel, and that πᾶς means everyone absolutely (i.e., righteous and unrighteous), then:
- πᾶς (“everyone”) = πᾶσα θυσία (“every sacrifice”)
Both the righteous and the unrighteous are sacrifices.
- πυρὶ ἁλισθήσεται (“shall be salted with fire”) = πᾶσα θυσία ἀλὶ ἁλισθήσεται (“shall be salted with salt”)
If fire destroys, yet salt preserves, how can the two clauses be parallel? Like salt,7 fire also signifies cleansing and purification.8 Like fire,9 salt may also signify destruction.10
Alford continues,11
Fire is the symbol of the divine purity and presence:—our God is a consuming fire, not only to his foes, but to his people: but in them, the fire shall only burn up what is impure and requires purifying out, 1 Cor. 3:13; 1 Pet. 1:7, 4:12, 4:17. This very fire shall be to them as a preserving salt.
Alford notes Isa. 33:14-15,12 in which it is written,
14 The sinners in Zion are afraid; fearfulness hath surprised the hypocrites. Who among us shall dwell with the devouring fire? who among us shall dwell with everlasting burnings? 15 He that walketh righteously, and speaketh uprightly; he that despiseth the gain of oppressions, that shaketh his hands from holding of bribes, that stoppeth his ears from hearing of blood, and shutteth his eyes from seeing evil; KJV
Isaiah does not say that no one will dwell with the consuming/devouring fire (אֵשׁ אֹוכֵלָה) and everlasting burnings. Rather, he positively answers that the righteous will. On the other hand, “the sinners in Zion are afraid.”13
Accordingly, in Mark 9:49, the righteous are purified from sin when salted with fire, while the unrighteous are devoured when salted with fire. However, lest one believe that the fire permanently destroys the unrighteous, “their worm does not die” — that is, they are eternally “tormented in this flame.”14 Everyone will be salted with fire; fire will react differently according to one’s righteousness. The righteous will be purified, while the unrighteous will be tormented, just as salt may be used to signify either preservation/purification or destruction.
References
Alford, Henry. The Greek Testament. Vol. 1. Boston: Lee and Shepard, 1878.
Kimchi, David (דוד קמחי). Peirush al Sefer Tehillim (פירוש על ספר תהלים). Jerusalem: 2004.
Lightfoot, John. Horae Hebraicae et Talmudicae: Hebrew and Talmudical Exercitations. Trans. Gandell, Robert. Vol. 2. Oxford: UP of Oxford, 1859.
Footnotes
1 Vol. 1, p. 380
2 Matt. 23:33
3 p. 83-84
4 Vol. 2, p. 425
5 Vol. 1, p. 380
6 ibid
7 cp. Eze. 16:4; 2 Kings 2:20-21
8 cp. Mal. 3:2-4; Zec. 13:9
9 cp. Deu. 9:3
10 cp. Jdg. 9:45
11 Vol. 1, p. 380
12 ibid
13 Isa. 33:33
14 Luke 16:24