When Rabbi Yosef Rosen, the famed Rogitzover Gaon, was 17 years old, he travelled around “to see if the world knew how to learn at all.”
One of his stops was in Lublin, and as per the suggestion of Rabbi Shneur Zalman Fradkin, the Toras Chessed, he visited Reb Tzadok HaCohen, who served as a Rebbe in the city.
Upon arriving at Reb Tzadok’s home, he attempted to engage the Rebbe in Talmudic debate, but the Rebbe interrupted him, asking the young genius: “Do you have a specific question to ask?”
When the young Rabbi Yosef responded that he merely wishes to debate but has nothing in particular to ask, Reb Tzadok looked at him for a long moment and told him:
“Listen up young man. I too was young like you at one time. During those years, I attempted to prove my prowess in Talmudic debate. I argued with countless Torah giants and I was never bested. However, upon visiting the Tzadik of Ishbitz, I became aware that this is not the proper path. The main objective in learning is that one’s Torah study should be infused with the fear of Heaven. On this the Talmud (Brachos 33b) states: ‘The Holy One, blessed be He, has in His treasury naught except a store of the fear of heaven, as it says (Yeshaya 33:6), “The fear of the Lord is His treasure.”’”
“In general,” continued Reb Tzadok, “What does G-d ‘gain’ if I win over you or you win over me? Instead, I suggest that you chose a Rebbe who will teach you a true path to Torah. Only then will you merit ‘the crown of Torah.’”
When the Rogitzover Gaon left Reb Tzadok’s abode, he was overheard murmuring to himself, “Woe, the words of this old man permeate me to the bone.” Indeed, after this event, Rabbi Yosef Rosen often visited Rabbi Shlomo Zalman Schneersohn, the Chabad Rebbe of Kapust.
(HaRogatzovi, Pg. 24)