One of the most renowned traits of the great Volozhiner rosh yeshivah, Rav Naftali Tzvi Yehudah Berlin zt”l, otherwise known by the acronym of his name, Netziv, was his intense diligence. Even as a teenager, he developed a reputation as a tremendous masmid. He studied Torah with great fervor, and it was this trait that enabled him to acquire universal renown. Still a boy, at the age of 11 he was sent to study at the famous Volozhin Yeshivah, where Reb Itzele Volozhiner zt”l, the Rosh HaYeshivah, took him as his son-in-law at the tender age of 13 years old. The Netziv came to live in Volozhin, and there he once again isolated himself in incessant study and made his nights into days of Torah study. Truly extraordinary stories are told concerning his diligence in study. For example, when he felt sleepy, he would put his feet in a bucket of cold water to continue studying.