The Salt of Friendship

Oath-taking, in many cultures, is a ceremony involving salt, just as the act of swearing may employ blood or iron as a sign denoting a person's unbreakable word. Salt is shared at table, in a context of order and contentment. Traditional Bedouin will never fight a man with whom they have once eaten salt. When the Lord God of Israel made a covenant with the Jews, it was a Covenant of Salt, denoting an unalterable bond of friendship. It also meant that the Jews had settled down in the Promised Land, had ceased to be sheep-herding nomads, and would now eat the fruit of their harvests, cooked and seasoned with salt.

Margaret Visser, Much Depends on Dinner - the extraordinary history and mythology, allure and obsessions, perils and taboos of an ordinary meal, 67.