For six months, the messengers go forth: for Nissan, because of Pesach; for Av, because of the Fast; for Elul, because of Rosh Hashanah; for Tishrei, because of the [proper] determination of the holidays; for Kislev, because of Chanukah; for Adar, because of Purim. And when the Temple was in existence, they went forth also for Iyar, because of [the] minor Pesach.