The Mishna only enumerates the list of people that do not deserve to be resurrected in their own merit. However, Hashem will show his great mercy and resurrect them anyways.
Dear Reader sh’yichyeh
This week we are going to discuss the introduction we say before each chapter of Pirkei Avos: All Israel have a share in the World To Come, as it is stated, And Your people are tzaddikim (righteous) they shall inherit the land forever, they are the branch of My planting, the work of My hands, in which I take pride.
The reason we start each recitation of Pirkei Avos with this Mishna is because we learn these chapters in the weeks leading up to Shavuos, as a preparation for receiving the Torah. The first step to that is improving in Ahavas Yisroel (see Rashi to Shmos 19:2). We therefore remind ourselves that every Jew has a portion in Olam Haba, and it is not (G-d forbid) beneath us to help him physically or spiritually. (Likkutei Sichos 1:262-3)
A simple reading of this Mishna indicates that all Jewish people will be resurrected in the times of Moshiach. However, the Mishna then enumerates several categories of people — sinners — who will not have a portion in the resurrection. One of the types is a person who does not believe in the resurrection. Because Hashem punishes “measure for measure,” this person does not merit being a part of the resurrection.
However, the Rebbe explains (Igros Kodesh Vol. 1, pp. 141-153) that even these people have ways to “join” the resurrection:
1) If the individual repents, even at the end of his/her life. This is written clearly in Rambam, Hilchos T’shuva;
2) If this individual has a very righteous son. This is based on the Talmud (Sanhedrin 104a) that states, “A son brings merit to his father.” This is true even if the parent did not do t’shuva. It also applies even if the son does not pray that the father be granted resurrection. The same would be true if the father was a righteous man and the son was a sinner;
3) If other righteous people pray on behalf of the individual. Included in this category is if others give tz’daka in this person’s honor. This holds true even if the person does not have a righteous descendant. (See Chagiga 15b).
4) If the sinners were embarrassed after their death, it helps them enter the World of Truth. This can be derived from the statement in the Talmud Yerushalmi (Kilayim 9:3) regarding the sinner Yerovam. It states that since his body was burned years after his death, he will be resurrected.
5) Even if one does not have any of the above merits, his soul will be resurrected nevertheless. Most of us are reincarnations of previous souls. The soul of a body that does not merit resurrection will join another part of its soul reincarnated in a different body. (See Seifer HaGilgulim, Chapter 5.)
6) Other commentaries add: The Mishna only enumerates the list of people that do not deserve to be resurrected in their own merit. However, Hashem will show his great mercy and resurrect them anyways.
From the above it is clear that every soul will be resurrected into a physical body in the time of T’chiyas HaMeisim.
Rabbi Avtzon is the Rosh Yeshiva of Yeshivas Lubavitch Cincinnati and a well sought after speaker and lecturer. Recordings of his in-depth shiurim on Inyanei Geula u’Moshiach can be accessed at http://www.ylcrecording.com.