LEV970 Alongside the[] moral exhortations and administrative actions taken by the halachic authorities to prevent economic suffering through restraints on the market mechanism, additional redress was provided through the application of the just price -- ona’ah -- limitation. The concept of ona’ah does not seem to flow merely from a concept of fraud or theft but rather as a form of exploitation in commercial transactions. It is instructive that the codes deal with it in the laws of buying and selling and not together with those of theft. There is valid ground to consider it primarily as a price different from that of the market price, as a result of lack of knowledge on the part of one of the parties or the use of undue influence by either of them. The basis for this interpretation lies in these observations: 1. The rabbinic concept of just price -- ona’ah-- derives from the biblical verse (Leviticus 25:14). In most places in the Bible where the word ona’ah is used, it refers to the exploitation of status or strength as for instance in the commandments (Exodus 22:20) “And a stranger you shall not oppress” and the parallel injunction in Leviticus 19:33. 2. All the commandments forbidding theft or robbery are understood to include non-Jews as well, whereas ona’ah applied only to Jews. Thus, it cannot be understood as fraud or theft, but rather as an extra duty devolving on the Jew to refrain from taking advantage of a position of, say, superior information. This duty could be implemented only in a reciprocal relationship; Therefore, it had to be limited to Jews only. 3. Ona’ah exists not only in business transactions but also in speech (ona’at d’varim). For instance, one is not allowed to vex a convert to Judaism by saying to him, “Remember the actions of your idolatrous ancestors.” The sages of the Talmud, commenting on this example, pointed out that such “Ona’ah in speech is far more serious than ona’ah in business, since the latter can be rectified by restitution, whereas the injury inflicted by speech cannot be. Ona’ah in business, after all, only affects one’s material goods, whereas one’s very being is affected by other forms of ona’ah. In the biblical text [Leviticus 25:17], the name of God is added to the injunction against [i.e., that which is traditionally understood to prohibit] ona’ah in speech but not to that [in Leviticus 25:14, quoted above] concerning ona’ah in business, making it a far more serious crime. Talmud Bavli, Baba Metzia 58b. Additional evidence that the concept of the just price is primarily a moral concept, concerned with the exploitation of ignorance or duress, may be seen from some of the halakhot in the codes, which disallow the claim of ona’ah in cases of full disclosure. Thus, for example: [Mishneh Torah, Hilkhot Mekhirah, chapter 13, halakhah 4, based on the Baraita, Baba Metzia 51b].