An excerpt from Making of Chassidim about a chossid of Ba’al Shem Tov observing other Jews davening:
Reb Mordechai also recited Tikkun Chatzos along with several other Jews who had assembled for that purpose. When they finished reciting Tikkun Chatzos, it was already broad daylight, for it was at the beginning of Tammuz, [when the sun rises early]. Members of the chevrah Tehillim began to assemble; these were Jews who gathered in the beis hamedrash each day at three o’clock in the morning to recite Tehillim. Most of these Jews were tradesmen: tailors, cobblers, butchers, coachmen, and other village workmen.
When a few minyonim of Jews had assembled, one of the chevrah Tehillim members began reciting: “Fortunate is the man who does not follow the counsel of the wicked.” The others immediately began following along, with such delight and devotion that Reb Mordechai envied their staunch innocence and sincerity.
The facial expressions of the each of the Tehillim sayers reflected an innocent charm, and an inner devotion to what they were reciting. From time to time the tone of the sayers’ voices changed: now prayerful, now hopeful, now broken. One could tell by their faces that they were aware of, and understood, what they were saying.
Reb Mordechai was quite moved by these Tehillim sayers, and yet there was one thing he could not tolerate: the frigid and lifeless manner of these people. Their frigid and lifeless movements and sounds made a gloomy impression upon him.
“This is what misnagdim are like”, thought Reb Mordechai. “They are good Jews, pious and precious, but also frigid and lifeless. Buried within these Jews lies the untapped timeless treasure to which the Rebbe the Baal Shem Tov applied the verse, ‘For you will be [G-d’s] treasured land’; but they remain misnagdim all the same.”
But then Reb Mordechai thought to himself, “What about me, what am I? I myself am nothing but a dead herring!” He had once imagined himself to be the Holy One’s confederate, and expected that any day that the prophet Eliyahu would reveal himself to him.
The only difference was that G-d, blessed be He, had taken pity upon him, and caused events to evolve in such a way that he had ended up in a far-away land where he was privileged to meet the Baal Shem Tov. Within two years’ time he had rid himself of the coarse impurities in his character.
These frigid, lifeless, stiff Jews, along with their emaciated porush could also be saved by the Baal Shem Tov. The Rebbe, with his path of Divine service actually resurrected the dead; he turned cold into warm, and brought the dead to life. Compare, for example, [these Jews] with those simple Jews whom Reb Mordechai had seen in the village of Zaslov, where he had first heard the Baal Shem Tov’s name.
He remembered the faces of those Jews — those Tehillim sayers were also cobblers, tailors, coachmen, and butchers. But those Jews were alive, happy, reciting Tehillim with joy, davening with gladness, doing favors for one another with relish. Their ahavas Yisrael made them into one big family. True, their respect for the Torah was somewhat lacking — they were quite capable of addressing a Torah scholar by name, without adding the title Moreinu, and they might even address him using the familiar pronoun “du”, but nonetheless, they were truly cherished Jews.
Reb Mordechai davening himself, having mentally reviewed a teaching of Ba’al Shem Tov:
Each repetition of this teaching awoke within him a willingness and desire to engage in the avodah of prayer. So it was on the present occasion too. After Reb Mordechai returned from the stream where he had immersed himself, he began his preparations for davening. He repeated the Rebbe's teaching several times, and meditated deeply about it. Then, he commenced his davening.
At about ten o’clock in the morning, the city dignitaries began to assemble in the grave diggers’ shul for a meeting of the chevrah kadishah. A prominent and wealthy citizen of the town had just died (may we be spared). They had to decide what plot he was to be buried in, the price the chevrah kadishah was to charge for the grave, and on what civic improvements this money should be spent. The meeting lasted for several hours, and there was much shouting and screaming. But Reb Mordechai remained seated in the southwestern corner of the shul, completely oblivious to what was happening.
One of the men attending the meeting happened to notice the stranger sitting in tallis and tefillin, his eyes open, his face flushed, muttering a few words from time to time. His words were whispered, and it was difficult to make out what he was saying. Right in the middle, he would break into some kind of song with an unfamiliar melody. The one who first noticed it told several others, and soon all the men were staring at him, wondering who this stranger might be.
Just then, a few of the assistant grave diggers came, to ask the gabbai where they should dig the grave for the deceased. One of the grave diggers had been present the previous day between Minchah and Maariv, when Reb Mordechai had related that in Vohlynia-Podolia there lived a great gaon and tzaddik, a miracle-worker known throughout the region as the Baal Shem Tov.
The assembled dignitaries listened to the grave digger’s report with open mouths, as they remained sitting in the beis hamedrash gazing at the unknown Jew.
How strange! At twelve o’clock noon, a Jew sits in tallis and tefillin, apparently still davening! Hours passed, and these Jews still had not had their fill of watching the strange Jew daven. At last they heard the sounds of the funeral procession, and they left to join it.
As they marched along, they told the story of the unknown Jew who was sitting in the grave diggers’ shul and davening. The listeners were skeptical, so when they returned from the cemetery (Reb Mordechai was then up to Kerias Shema), a large crowd gathered to watch him daven. When Reb Mordechai finished davening, he removed a piece of bread from his bag, washed his hands, and ate the bread with some water. After this meal, he lay down on a bench to rest.