There were people who opposed the Chozeh and went so far as to say that the day that he died would be established as a day of joy and feasting.
When the Chozeh heard this, he said, "I promise you that the day of my death will be commemorated by all as a day of mourning. Even my opponents will fast on the day."
And so it was. He was nifter on Tisha B’Av.
May the tzadik’s memory be a blessing for all of Klal Yisroel.