Reply To: Sources for Ta'anis Esther

The Mishna Brurah writes that we fast on the 13 because that’s when the Jews went to war and before Jews go to war they fast just like Moshe Rabbeinu.He then explains that the fast is called Taanis Esther because Hashem sees and listens to people who are in distress.See the Aruch Hashulchan for another understanding.Also the Shulchan Aruch brings down some people fast 3 days split up like bhab.The Kaf Hachaim brings a diff reason why we fast see it inside very interesting reason.