This sugya, one of the best-known in the Talmud, is found in Bava Metzi‘a 21a–22b. The basis of the sugya is a debate between the two fourth-century Babylonian Amoraím, Abbaye and Rava.

Yeúsh is the technical term for abandonment of property when it has been stolen or lost without hope of recovery. The basic meaning of yeúsh is despair. Although in some circumstances yeúsh of stolen property gives title to the thief, this matter is dealt with at length elsewhere in the Talmud. In our sugya the reference is to yeúsh of lost property. The legal principle here is that if a man who has lost some of his property despairs, i.e. gives up all hope of ever recovering that property, the property is held to have become ownerless and the finder may keep it. According to the rule as stated in the Mishnah (Bava Metzi‘a 2: 1 and further) the normal procedure when one finds lost property is to have the find proclaimed in a public place such as a synagogue. This serves as a kind of lostproperty office. There finders and losers repair, the loser stating any distinguishing marks – siman,‘sign’, ‘means of identification’ – and if this tallies with the siman of the lost article the article is restored to its owner. Thus, since there is a procedure for its recovery, it is assumed that there has been no yeúsh where the lost article has a siman. Why should the loser despair of recovering his article since he knows of the procedure and stands a good chance of identifying his property and having it returned to him?