12. If someone was banned in a dream (i.e. had a dream that he was placed under Nidui), even if he knows the person who declared the ban against him, he needs ten people, proficient in Halakha, to lift the ban. If he can’t find [these], he must trouble himself, looking for them up until a Parsa’s distance (abt. 4 miles).
If he didn’t find [these], ten people who have [only] studied Mishna may lift his ban.
If he didn’t find [these], ten people who [only] know how to read the Torah may lift his ban.
If he didn’t find [these], ten people who can’t even read Torah may lift his ban.
If he didn’t find ten people in his place, even three may lift his ban.
Q1: Why would a dream about a ban have any Halakhic implications?
YE: From the Gemara itself (Nedarim 8a) it seems clear that this _may_ be an intended message from God. RAN (s.v. Nidahu) says: It is possible that he was banned by the agency of God (i.e. the one appearing in the dream to ban him was an agent of God); Tosafot (s.v. Tzarikh) says: Since a dream is like a bit of prophecy… A proper treatment of this issue is well beyond the scope of this list, however, it is clear from the Gemara (last chapter of Berakhot) and the Rishonim that dreams are not to be understood merely as internal psychological manifestations; there is always the chance that there may be a valid and Divine message somewhere in that dream.
Q2: If he can identify the person who banned him in the dream, why must he find ten people to lift it – why can’t he just ask that person to lift it?
YE: As RAN explained, the person appearing may not be a manifestation of that actual real-life person, rather an agent of God. Asking the real-life person for forgiveness may be a totally meaningless act.
Q3: Why ten people – why not a conventional Beit-Din of three?
YE: Since, as our Rabbis teach us (Avot 3:6) whenever 10 people are together, studying Torah, the Shekhina (Divine Presence) rests among them. Since it is possible that God has banned this person, we cannot lift the ban without His Presence.
Q4: Why the hierarchy of learning and literacy?
YE: As mentioned above (Q3), the reason for 10 is due to the Shekhina resting among them. Since the Shekhina rests among “10 who are studying Torah”, our ideal group are those who not only know, but can converse with each other about Torah. As we move down the “literacy and learning” scale, the group moves further from this description.
Rambam, Copyright (c) 1999 Project Genesis, Inc.