The sugya described here is Kiddushin 62a–63a. The sugya is appended to the Mishnah which rules as follows. If a man betroths a woman and one of them is a Gentile but he declares that he wishes the betrothal to take effect after his or her conversion to Judaism, the betrothal is invalid. Similarly, if he is a slave but he declares that he wishes the betrothal to take effect after he or she has been freed, it is invalid. Two further cases are: a man betroths a married woman, the betrothal to take effect when her husband dies; or a man betroths his wife's sister, the betrothal to take effect when his wife dies. Finally, there is the case of a man who declares to his neighbour: ‘If your wife will give birth to a girl she is betrothed to me.’ In all these cases the betrothal is invalid on the following principle: that which cannot take effect now because of some major legal objection does not take effect even when that obstacle is no more.

Davar she-lo ba le-‘olam, the term used in our sugya, means literally ‘a thing that has not yet come into the world’. The question is whether the conveyancing or transfer of something or of something being effected is valid if the thing is not yet in existence. This is formulated by the Amoraím as: ‘a man can transfer [lit. ‘make another acquire’] a thing not yet in existence [adam makneh davar she-lo ba le-'olam]’ or ‘a man cannot transfer a thing not yet in existence [eyn adam makneh davar she-lo ba le-‘olam].’