Still, we may wonder: Why does the Gemara repeat the above statement four times, and why specifically at the end of these masechtos? What is their connection to peace? The Aruch LaNer explains that there are four categories of shalom, peace. There is shalom bein adam la’Makom, peace between man and HaShem; shalom bein adam la’chaveiro, peace between man and his friend; shalom bein ish le’ishto, peace between man and his wife; and shalom bein guf u’neshamah, peace between physical man and his spiritual soul. Each of these four masechtos relates to one of these categories.
The masechta of Berachos discusses subjects such as Krias Shema, tefillah, and berachos, which unite man with his Creator in all aspects of his life. Hence, this tractate relates to peace between man and HaShem.
Yevamos deals with the laws of yibum, levirate marriage. Yibum is an act of kindness for the deceased brother whose name will be carried forward, and also to his widow. This is considered chesed for the living and the dead, and thus connects to shalom bein adam la’chaveiro. (See also Zohar on Bamidbar:259b.)
The section of the Torah (and Gemara) discussing the laws of the nazir (one who vows to abstain from certain forbidden behaviors in an effort to come closer to HaShem) follows the laws of the sotah, the unfaithful wife. Chazal (Sotah 2a) explain that this is to teach us that one who sees a sotah in her disgrace should vow to become a nazir and abstain from wine, for drinking wine leads to forbidden relationships. Nezirus is the reaction of a person who wants to ensure that his familial relationships stay strong. Thus, Maseches Nazir connects to peace between man and his wife, bein ish le’ishto.
Regarding Kerisus, the Aruch LaNer writes that the performance of mitzvos in This World is to benefit the nefesh that resides in the body, so that it should continue to exist even after the ruach, the living spirit, has separated from it. Also, doing mitzvos assures a constant bond between the nefesh that dwells on the earth, specifically at one’s gravesite, and the ruach, spirit, whose dwelling of honor is in the lower spheres of Gan Eden, as well as the neshamah, soul, which resides in the upper spheres of Gan Eden. This is the reason that we pray at the graves of tzaddikim, as there still exists a connection between the physical body and the spiritual neshamah.
However, when a person violates a sin, whose punishment is kareis, the nefesh is cut off from the ruach and the neshamah, as the pasuk says, “Ve’nechresah hanefesh hahi.” The consequences are twofold: First, the connection in This World, between the nefesh that resides in the body and his soul, has been severed. Second, there is no more hope that the individual will arise at the time of techiyas hameisim, the resurrection of the dead. This, says the Aruch LaNer, is the link between Maseches Kerisus and the shalom between body and soul in This World and in the World to Come. A person should keep away from those sins that are enumerated in the masechta and incur the punishment of kareis, which destroy the bond between guf and neshamah. If one has already sinned, chas ve’shalom, he should bring the appropriate korban and repent, so that the light of his neshamah, the ner HaShem, will remain burning within his nefesh.
