Siman 121

(18.) In the year 5565 [1804/5] between Pesach and Shavuos he traveled to Sharigrad and stayed there two weeks. And this journey was also a very great wonder, and he said to one who accompanied him [to the people who accompanied him]: "The world longs for when there will be like the Baal Shem Tov of blessed memory — " And suddenly he went out from there, and said that he is fleeing as from fire. And afterwards there were great conflagrations there several times. And he said: "Had the people of Sharigrad known the goodness I did for them etc. — even so, all this is better than ipush [a severe plague or pestilence], G-d save us." And it is understood from his words that he saved them through his sitting there from ipush, G-d save us. These are the journeys of the children of Israel — fortunate is the one who merits to know even one secret of his very wondrous journeys which had no ordinary meaning whatsoever. And he said at the time he traveled to Navoritch: "If the world knew the meaning of my journey they would kiss the footsteps of my feet — for in every single step of my journey I tip the entire world to the scale of merit."