How is Isaiah 66:17 to be understood if pork will become kosher when the Messiah comes?

Question

The Ritva, R. Yom Tov Asivelli (in the 13th century) wrote that pork will become kosher when the Messiah comes: (קידושין מט:)

ועליהם אמרו בהגדה למה נקרא שמו חזיר שעתיד הקב"ה להחזירו לישראל לעתיד לבוא

Why is it called Chazir? Because the Holy One will return it to Yisrael in the future.

In light of this, how is the context of Isaiah 66:17 to be understood?

With fire and with sword the Lord will judge all humanity; many will be slain by the Lord. Those who became holy and purify themselves, following their leader into the gardens, who eat pork, detestable animals, and mice, will meet their end together, says the Lord. Because of their actions and thoughts, I’m coming to gather all nations and cultures. They will come to see my glory.

Answer 1

The full quote from the Ritva is very interesting, but also makes your question a non question.

תשעה נטלו חזירים. יש שפירשו עמלק כדכתיב בו יכרסמנה חזיר מי^ער ועליהם אמרו בהגדה למה נקרא שמו חזיר שעתיד הקב"ה להחזירו לישראל לעתיד לבוא. ואין צורך לכך כי בספר הטבעים כתב שהצרעת ונגעים בחזירים הרבה בטבע:

Regarding the 9 out of ten measures of tzaraas in the world that the pig took mentioned in Kidushin 49b the Ritva wrote:

There are those that explain [this pig to mean] Amalek as it is written "wild boars gnaw at it" psalms 80:14. And upon them they expounded in Agada "why is its name 'Chazir', since Hashem shall return him to us in the the future". But there is no need for this as the books on nature write tzaraas and afflictions are many and natural in pigs."

(My translation)

So interestingly the drasha of the 'pig' returning in the future was brought by Ritva as not referring to the animal known as the pig, but rather referring to the nation known as Amalake.

The Ritva ended off by saying this drasha is unnecessary for reading the gemara due to scientific knowledge, but the way he brought the drasha means the pig will not actually become kosher again.

(It's not clear to me what source he is referring to. My Ritva says Vayikra Rabba ch. 13, but I see a different drasha there about this passuk.)

Answer 2

Isaiah 66:17

"Those who prepare themselves and purify themselves to the gardens, [one] after another in the middle, those who eat the flesh of the swine and the detestable thing and the rodent, shall perish together," says the Lord.

Speaks of those who deliberately flout the halachos of the Torah, such as eating חזיר, before the mashiach comes. They will be punished. The discussion about the pig changing to chew its cud after the mashiach comes will therefore not apply to those who violated the halacha previously.

Answer 3

The Ohr ha-Chaim [on Lev. 11:7] says that in the Messianic Age God will change the pig's anatomy so that it chews its cud, and thereby become kosher.

What Isaiah said will happen first. At a later time the pig will become kosher.

Answer 4

In the time to Come the Holy One, blessed be He, will announce "Anyone who didn’t eat pig’s flesh may come and collect his reward." It is difficult – why announce about a negative mitzvah of eating, any more than the rest of the negative mitzvahs of other forbidden activities which do not pertain to eating. Further, why make such an announcement about pig, and not about the rest of the impure animals and torn animals [which are also forbidden to eat]?

According to what is said about the Yetzer Hara, that it is made from the power of the pollution of the primordial snake, who caused Adam and Eve to sin and this is the reason why it is fitting to blame him for all the sins. And in particularly the sins of forbidden eating, for the sin of Adam and Eve – from which was drawn the pollution of the snake, from which the lowly Yetzer Hara comes – it was the sin of eating from the Tree of Knowledge. But this was [the Tree of Knowledge of] good and evil, as stated in the verse, and the good was revealed, as it states: "and the woman saw that the tree was good for eating", that the good was revealed in it and she saw it, but the evil was submerged within it like the venom of a snake which is hidden within it and is not seen from the outside.

The pig is similar to the tree which, contained good and evil, for it possesses a sign of purity which is revealed and visible from the outside – it has split hooves, which is visible to all. But it has a sign of impurity in that it does not chew its cud, and this sign of impurity is hidden and not openly seen. Thus it is explicitly stated in the verse, "the pig, because it has split hooves and does not chew its cud, is impure to you."

Read the full article: https://www.chabad.org/kabbalah/article_cdo/aid/2518058/jewish/Permitting-the-Pig.htm