The Geneva Deal Gives Good Reason to Fast This Tenth of Tevet

It seems that a new dangerous regional superpower is circling the walls of Jerusalem and preparing for a siege.

One of the first times we read about the minor Jewish fast day Tenth of Tevet is in the Talmud of Rosh Hashanah (18b). In Mishnaic times, messengers would be sent to Diaspora communities from Jerusalem to declare Rosh Chodesh during the six months that contained holidays, in order to standardize the calendar for festival observance.