(9) But take utmost care and watch yourselves scrupulously, so that you do not forget the things that you saw with your own eyes and so that they do not fade from your mind as long as you live. And make them known to your children and to your children’s children: (10) The day you stood before the LORD your God at Horeb, when the LORD said to Me, “Gather the people to Me that I may let them hear My words, in order that they may learn to revere Me as long as they live on earth, and may so teach their children.”
(31) See, a time is coming—declares the LORD—when I will make a new covenant with the House of Israel and the House of Judah. (32) It will not be like the covenant I made with their fathers, when I took them by the hand to lead them out of the land of Egypt, a covenant which they broke, though I espoused them—declares the LORD. (33) But such is the covenant I will make with the House of Israel after these days—declares the LORD: I will put My Torah into their inmost being and inscribe it upon their hearts. Then I will be their God, and they shall be My people. (34) No longer will they need to teach one another and say to one another, “Heed the LORD”; for all of them, from the least of them to the greatest, shall heed Me—declares the LORD. For I will forgive their iniquities, And remember their sins no more.
ת"ר בגד שאבד בו כלאים ... אבל עושה ממנו תכריכין למת אמר רב יוסף זאת אומרת מצות בטלות לעתיד לבא
The Rabbis taught An article of clothing in which a thread of kilayim [prohibited combination of fabrics... can be used to make a burial shroud. Rav Yosef says: This means that mitzvot will be nullified in the coming days....
(ז) רַבִּי פִּנְחָס וְרַבִּי לֵוִי וְרַבִּי יוֹחָנָן בְּשֵׁם רַבִּי מְנַחֵם דְּגַלְיָא, לֶעָתִיד לָבוֹא כָּל הַקָּרְבָּנוֹת בְּטֵלִין וְקָרְבַּן תּוֹדָה אֵינוֹ בָּטֵל, כָּל הַתְּפִלּוֹת בְּטֵלוֹת, הַהוֹדָאָה אֵינָהּ בְּטֵלָה,
(7) Rabbi Pinchas, Rabbi Levi and Rabbi Yochanan [said] in the name of Rabbi Menachem from Gallia: In the time to come, all sacrifices will be annulled - but the sacrifice of thanksgiving will not be annulled. All prayers will be annulled, but the prayer of gratitude will not be annulled.
אָמַר רַבִּי אָבִין בַּר כַּהֲנָא אָמַר הַקָּדוֹשׁ בָּרוּךְ הוּא (ישעיה נא, ד): תּוֹרָה חֲדָשָׁה מֵאִתִּי תֵצֵא, חִדּוּשׁ תּוֹרָה מֵאִתִּי תֵצֵא.
Says Rabbi Avin Bar Kahana: Hashem says "Torah Will Go Out From Me", A New Torah Will Go Out From Me.
Yalkut Shimoni, Mishlei, 944
In the future, all the holidays will be nullified, and the days of Purim will never be nullified…
Yerushalmi, Megillah 1:5
Rabbi Yochanan said: the [Books of] Nevi’im and Ketuvim will be nullified in the future and the Five Books of the Torah will not become nullified in the future…Rabbi Shimon ben Lakish says: Megillat Esther and halachot will also not become nullified in the future.