Or HaChaim on Deuteronomy 29:20/אור החיים על דברים כ״ט:כ׳

1ומחה ה׳ את שמו מתחת השמים, "and G'd will blot out his name from under the heaven." Remember that the root of the souls of all the Israelites originates in a sacred part of heaven, immediately below the throne of G'd.

2In this instance, a unique instance, the Torah threatens that in spite of the sacred origin of his soul, it will be utterly blotted out in retribution for the devious plan to be parasites and to benefit from the blessings granted to the Torah-observant majority while at the same time violating all the commandments.

3 והבדילו ה׳ לרעה, "And G'd will single him out for misfortune, etc," This seems a paradox. After the soul of the person has already been blotted out, how can G'd separate it from other souls? We may have to understand this in connection with Isaiah 60 that all the Jewish souls originate in the same place as we have been told by Vayikra Rabbah 4,6 on Genesis 46,26 where all the 70 souls of the family of Jacob are described as כל הנפש, "the whole soul" (singular), as opposed to the souls of Esau which are described in the plural (Genesis 36). When the Torah writes that "G'd will blot out his name from under the heaven, this means that G'd will not take action against this man and consign him to the forces of the קליפה which is here called רעה, "evil," until He has separated his soul. This "separation" implies certain restrictions G'd imposes on the forces of the קליפה concerning the soul of this person. G'd makes it a point to always set some limits on the forces of destruction though He Himself allocated to these forces the parameters within which they may operate. We have quoted an example of such restrictions placed on the forces of destruction when Rava's father warned his son not to sleep in his bed in order not to be killed by these forces ( Taanit 24).

4מכל שבטי ישראל, from all the tribes of Israel. Seeing that a Jewish soul has an affinity to all the tribes, G'd has to separate this person's soul from all the tribes lest the evil which befalls it will have negative repercussions on those tribes.

5Alternatively, the word והבדילו may mean that after G'd has wiped out the name of this person, i.e. his soul, from under the heaven, He will transfer it to a spiritual region reserved for destroying such souls. ככל האלות, "like all the curses, etc." this means that the רעה, "evil" in store for this soul will include all the curses mentioned in the Torah thus far.