Pentecost is the Greek name (“fiftieth”) for the feast the Torah calls Weeks, in Hebrew Shavuot: kept fifty days after Passover, when the firstfruits of the wheat harvest were brought to God (Leviticus 23:15–17). That is why devout Jews “from every nation under heaven” fill Jerusalem in this chapter: it was a pilgrimage feast, one of the three yearly appearances.

Jewish tradition also came to keep Shavuot as the anniversary of the giving of the Torah at Sinai; the Talmud states plainly that it is “the day on which the Torah was given” (Pesachim 68b). The synagogue still reads Ruth, the harvest-season story of a Gentile grafted into Israel, at this feast by long custom. On that day, in that city, the Spirit was given and three thousand were gathered in: the resonance is the reader's to weigh.