Rav Naftali Amsterdam was a Talmid of Rav Yisroel Salanter. He once came to his Rebbe and said, ‘Rebbi, if I had the head of the Shaagas Aryeh, and if I had the Neshamah of the author of the Yesod V’Shoresh Ha’Avodah and if I had your good Middos, then I could truly be a Servant of Hashem.’
Rav Yisroel Salanter responded to him, ‘Naftali, with your head, and with your heart, and with your good personality traits, you can be Naftali Amsterdam! That is all you have to be. You do not need to be the Shaagas Aryeh, or Rav Yisroel Salanter, or anybody else. Just be YOU, and that is how you will serve Hashem!’