Rabbi Refael of Bershid was once visiting a certain town. On Tisha B’av, he was informed of a bitter feud between two groups, and was asked to serve as mediator.
“We assume, however, that you will not want to hear the two sides until tomorrow, since today is a fast day,” they told him.
“On the contrary,” responded Rav Refael. “The destruction of the Temple was caused by unwarranted hatred (Yoma 9b). What is more appropriate than trying to promote peace and brotherhood on this day?” ~ Midrash Pinchos as quoted by R’ Zelig Pliskin