 A Midrash taught that according to some authorities, Israel fought Sihon in the month of Elul, celebrated the Festival in Tishri, and after the Festival fought Og.The Midrash inferred this from the similarity of the expression in "And you shall turn in the morning, and go to your tents," which speaks of an act that was to follow the celebration of a Festival, and the expression in "and Og the king of Bashan went out against them, he and all his people.