Nedarim

R. Joseph said: If one was placed under a ban in a dream, ten persons are necessary for lifting the ban.  They must have studied halachah;  I but if they had only learnt [Mishnah],  they cannot lift the ban; but if such as have studied halachah are unavailable, then even those who have only learnt Mishnah], but had not studied [halachah] will do. But if even such are unavailable, let him go and sit at the cross-roads, and extend greetings  to ten men, until he finds ten men who have studied halachah.  Rabina asked R. Ashi: If he knew [in his dream] the person who placed him tinder a ban, can this person lift the ban? — He answered: He might have been appointed [God's] messenger to ban him, but not to revoke it. R. Aha asked R. Ashi: What if one was both banned and readmitted  in his dream? — Said he to him: Just as grain is impossible without straw,