Samuel Sislen of Washington, D.C., writes:
“Jews have traditionally greeted one another ‘Shalom aleykhem’ and responded with the words inverted. Arabic speakers greet each other, ‘Salaam aleykum’ and also respond with the words reversed. And I have been told that some Christian services begin with the leader saying, ‘Peace be unto you,’ and the congregation responding, ‘And unto you.’ Where does this greeting originate and how did it spread?”
The greeting Mr. Sislen asks about is an ancient one. It does not, it is true, appear in the Bible. There, the expression is simply shalom, “peace,” or shalom lekha [“peace to you,” second-person masculine singular], shalom lakh [second-person feminine singular], etc. It seems to have originated in one of two ways.
One would have been as an assurance, when two people met, that the greeter had peaceful intentions; this is how it is used in several biblical passages, as in the story of Joseph, whose servant says to his frightened brothers, “Shalom lakhem,” i.e., “Don’t worry, you’ll be treated well.”
Or perhaps it started as a question, as in the story in Kings in which the prophet Elisha asks the Shunamite woman, “How are you? (“Ha-shalom lakh? “ — literally, “Is all well with you?”), and is answered “All is well” (“Shalom”). Besides meaning “peace,” the biblical shalom has the sense of “well-being,” and to this day the standard way of asking “How are you” in Hebrew is “Ma shlomkha?” – literally, “What is your well-being?”
In its form of shalom aleykhem, the greeting is first found in Hebrew in the early rabbinic period. By then, though, it was an everyday one. We know this from a comment in the Jerusalem Talmud on the Mishnaic tractate of Shevi’it, which deals with agricultural matters. In the Mishnah, the ruling is found that a Jew encountering a non-Jew farming the field next to his should always say hello “for the sake of good relations.”
How, the Talmud asks, should this be done? The answer is: “As one greets a fellow Jew, with a shalom aleykhem.”
Why the expression had aleykhem, with the plural form for “you” rather than alekha, the singular form, is difficult to say.