Q: I am purchasing a bedroom set second-hand. I have already paid the seller in cash and arranged to come by the next day to collect the furniture. Does either side still have the possibility of backing out?

A: In a famous statement, R’ Yochanan teaches that cash payment finalizes a transaction according to Torah law. (B.M. 47b) However, the Mishna (B.M. 44a) teaches that for transactions between Jews, the Sages revoked the effect of cash payment and enabled retracting until an act of transaction (kinyan) is performed. In the case of a bedroom set, this would require picking up or dragging the beds (C.M. 198:1).

Thus, both sides still have the legal ability to back out before the items are collected. The Sages strongly discouraged doing so, and imposed a curse (mi shepara) on one who does not uphold his commitment (204:1, 4). The sale can easily be made binding though performing a kinyan sudar, whereby the buyer hands his handkerchief or pen to the seller in exchange for title to the beds (195:1). Moreover, nowadays cash payment might be considered a kinyan based on the concept of situmta – common business practice.