The last mishnah in Masechet Uktzin states:
אמר רבי יהושע בן לוי: עתיד הקדוש ברוך הוא להנחיל לכל צדיק וצדיק שלש מאות ועשרה עולמות, שנאמר,”להנחיל לאוהבי יש ואצרתיהם אמלא.” -משלי ח:כא
Rabbi Yehoshua ben Levi said: In the future, the Holy One, Blessed is He, will cause every righteous person to inherit 310 worlds, as it says, “to cause my beloved ones to inherit, and their treasure houses shall I fill”. (The word “יש” in the verse has the numerical value of 310.)
The Netziv in his introduction to Ha’emek Shayla explains that this statement of Rabbi Yehoshua ben Levi refers to the 310 areas of technical expertise which are necessary for a landmark תלמיד חכם (Torah scholar) to master in order to adjudicate the myriad areas of Halacha. How is it possible for one to spend their days and nights engrossed in learning Torah and at the same time master all the sciences that are necessary to apply the rulings of the Torah to our physical world? The Netziv explains that the Holy One, Blessed is He will give these bodies of knowledge to the tzadik as an inheritance, i.e. without the necessity to toil; he will acquire them as a gift. This statement of Rebbi Yehoshua ben Levi aptly describes Rav Belsky. Although Rav Belsky never went to college or had any formal technical training, he truly mastered all areas of technical expertise and was thus able to uniquely rule in fields that are closed to many others.
Only the select few, including Rav Belsky, who have attained an exalted level of proficiency in the many technical and elusive disciplines, are qualified to lead the Jewish People in some of the most sensitive areas of Halacha.
How did Rav Belsky do it? As a senior rosh yeshiva and posek, whose hundreds of talmidim and countless members of the tzibbur required his time and guidance at all hours, it could not have been humanly possible to master and keep current with the many advanced and intricate חכמות (disciplines) under the circumstances. However, הקדוש ברוך הוא, the Holy One, Blessed is He, endowed this knowledge upon Rav Belsky, for such is the way of Hashem, to gift his select few with talents and knowledge that by far exceed their limited human abilities to acquire them. Yes, Rav Belsky immersed himself in the pools of wisdom with an unquenchable thirst, but the mastery attained by Rav Belsky was nothing short of miraculous, as Hashem enabled him למעלה מן הטבע, in a supernatural manner, to acquire indescribably vast technical expertise far beyond that which any human can achieve on his own.
יהי זכרו ברוך – May his memory be a blessing.
By Rav Hershel Schachter, Senior Halachic Consultant of OU Kosher