Zacarias 8:18-23

(18-23) This fourth section gives at last all that the prophet deigns to answer concerning the fast of the fifth month (Zacarias 7:3), and also concerning the other fasts. On the 9th or 17th of “the fourth” month (Tammuz) Jerusalem was taken by Nebuchadnezzar, in the eleventh year of Zedekiah (Jeremias 39:2; Jeremias 52:6). On the tenth of “the tenth” month (Tebeth) siege was laid to Jerusalem by Nebuchadnezzar, in the ninth year of Zedekiah (2 Reis 25:1; Jeremias 52:4). As, on account of their sins, their feasts had been changed into fasts, and their days of rejoicing into mourning (Amós 8:10), so now the prophet promises that if only they will keep the required conditions their fasts should be transformed into feasts. No express command is given with respect to the abolition of the fasts; but according to Jewish tradition (T.B. Rosh Hashshanah, 18 b), when the nation was in peace and prosperity the fasts were held in abeyance; when it was in trouble again the fasts were resumed. Since the destruction of the Temple by Titus, the Jews have kept the following fasts: the seventeenth of Tammuz, the ninth of Ab, the third of Tishri, and the tenth of Tebeth, on account of various calamities which took place on those days.