A gentile once came to Shammai asking to be made a proselyte, but only on condition that he be taught the Written Torah and not the Oral. Shammai sent him away with sharp rebuke. The same seeker came to Hillel with the same terms, and Hillel accepted him at once.
On the first day Hillel taught him the letters in their proper order, aleph, bet, gimel, dalet. On the second day Hillel reversed the order. The new student protested: "But you did not teach me so yesterday!" Hillel answered gently, "You trusted me in what I taught you then. Why, then, do you not trust me now in what I tell you concerning the Oral Torah?"
As the Talmud records in Shabbat 31a, the man became a full proselyte. Where Shammai met the stranger with a builder's rod, Hillel met him with a teacher's patience — and patience won a soul for Torah.