Once, when the Baal Shem Tov arrived in a certain village, he followed his usual practice of expressing his strong love for the simple Jews living there - and evoking from them their genuine and deeply felt belief in, and gratitude to, G-d.
There lived in that village an elderly Jewish scholar, known as a gaon, who had totally removed himself from worldly activities. For fifty years he had studied Torah all day and all night in isolation. He would fast and sit in his tallis and tefillin until the late afternoon prayers of Minchah. Only after the evening service did he allow himself to taste some bread and water.
When the Besht visited the gaon in his little corner of the shul, he asked the gaon about his health and whether his needs were being met. This was the Besht's method of evoking praise to the A-lmighty in the form of an answer such as, "Thank G-d, everything is fine with me." The Besht was, as yet, unknown as the great spiritual master that he would soon be revealed to be. The gaon, therefore, preferring to remain undisturbed with his learning - and not recognizing the greatness of the Besht - ignored him.
The Besht persisted with the same question until the gaon got angry and pointed to the door (for the Besht to leave). The Besht told the gaon, "Why don't you give Hashem His parnassah (sustenance)?"
Upon hearing these cryptic words from an unknown peasant, the gaon's irritation increased.
The Besht read the thoughts of the gaon and explained to him: "The Jews exist on the sustenance with which G-d provides them. On what sustenance does G-d dwell?" Answering his own question, the Besht continued: "King David recounts in Tehillim (22:4): 'And You, Holy One, are enthroned upon the praises of Israel.' The praises that Jews give to G-d, my brother, are His sustenance."
Chassidic Discourses, vol. 2, p. 256, Likkutei Sichos, vol. 7, pp. 135-136