Contrary to common opinion, the traditional Jewish greeting of “Shalom aleikhem” is not a wish for peace. It is a fulfillment of the ancient enactment to greet others with God’s name, using the appellation of Shalom to refer to God. The Mishnah (Berakhos 54a) describes the establishment of this practice but leaves its origin ambiguous, resting in my opinion on a single letter in the text.
Many commentators assume that Boaz, the character from the biblical book of Rus, enacted this practice. Among them are Malbim (Rus 2:4) and Maharatz Chajes (Mevo HaTalmud ch. 10). However, I suggest that this historical attribution is based on only one of two posssible readings.
The Mishnah states that “they” enacted the practice of greeting with God’s name. The next statement in the Mishnah cites the verse in which Boaz greets his workers with “God be with you” (Ruth 2:4). Some read this as implying that Boaz was the first to establish this practice. However, this is not necessarily the case.
The Rivan (Makos 23a sv. u-she’eilas) offers two explanations for this enactment: either it established an obligation for this otherwise permissible practice or it established permission for this otherwise forbidden practice. According to the latter approach, it is forbidden to say God’s name in vain. However, due to concern for interpersonal harmony or in order to decrease the amount of theft by bringing God’s name into regular conversation, “they” established that people use it in formal greetings as a proactive measure to prevent loss of Torah. This would explain why the Mishnah continues with the classical exegesis permitting violating the Torah in order to preserve it.
According to this reading, the Boaz precedent is highly significant. He would have been violating a prohibition if not for this emergency enactment. Additionally, it seems likely that the Bible mentions this curious behavior–otherwise forbidden–to teach that Boaz was the one to enact this behavior.
However, the Rambam, in his commentary to this Mishnah, reads the text differently. The Rambam posits that saying God’s name in a greeting is entirely permissible. The verse about Boaz is cited as proof that this activity is unproblematic. (And the subsequent discussion of violating the Torah in order to preserve it is really about the importance of enactments in general.) The Rambam seems to follow the Rivan’s first interpretation. Greeting with God’s name is always permissible and this enactment turned it into a requirement, not for any emergency reason but because it is simply a good thing.
According to the Rambam and the Rivan’s first interpretation, we no longer have any indication that Boaz instituted this practice. If anything, the Mishnah implies that this happened after Boaz’s time because otherwise we have little proof from his actions about the base law. Then who enacted it?
I speculate that perhaps this was among Ezra’s enactments. Rashi (Berakhos 54a) states the previous enactment in the Mishnah emanated from Ezra’s court. There are two versions of the introduction of the greeting enactment. Some texts have it “and they enacted” and some have it without the prefix meaning “and.” If the “and” truly belongs, then the Mishnah implies that Ezra’s court also instituted the greeting enactment.
The Vilna Shas has the “and” but the Kaufman manuscript does not. R. Yosef Kafach, in his edition of the Mishnah with Rambam’s commentary, indicates that some manuscripts he used has the “and” but his grandfather’s did not.
If not Ezra then some post-Judges era court enacted that we greet each other with God’s name. Thousands of years later, “Shalom aleikhem” is still a frequently heard greeting in traditional Jewish communities.
(Note that R. Yehudah Assad (Responsa Yehudah Ya’aleh, Orach Chaim no. 9) assumes that Ezra and his court instituted this enactment but he has a very different way of explaining the texts.)