משנה אויף בראשית 30:32

There are four rules with regards to those who sell:If one has sold good wheat and it turns out to be bad, the buyer can retract. If he sold bad wheat and it is found to be good, the seller can retract. [But if one sold] bad wheat and it is found to be bad, or good wheat and it is found to be good, neither may retract. [If one has sold] dark wheat and it turned out to be white; Or white and it turned out to be dark; Or [if he sold] olive wood and it turned out to be sycamore wood; Or sycamore wood and it turned out to be olive wood; Or [if he sold] wine and it turned out to be vinegar; Or vinegar and it turned out to be wine; Either of them may retract.