The prophet answers the query (Zec 7:3) as to the fast in the fifth month, by a reply applying to all their fasts: these are to be turned into days of rejoicing. So Jesus replied to His disciples when similarly consulting Him as to why fasting was not imposed by Him, as it was by John the Baptist. When the Sun of righteousness shines, tears are dried up (Mat 9:15). So hereafter (Isa 35:10).