a Talmudist, halakhist, kabbalist, and the foremost leader of mitnagdic (non-hasidic) Jewry of the past few centuries. He is commonly referred to in Hebrew as ha-Gaon he-Chasid mi-Vilna, "the saintly genius from Vilnius".
Through his annotations and emendations of Talmudic and other texts he became one of the most familiar and influential names in rabbinic study since the Middle Ages, counted by many among the sages known as the Acharonim, and ranked by some with the even more revered Rishonim of the Middle Ages.
A man of valor is one who is mighty of heart with perfect trust to perform mitzvot at all times and to meditate upon the Torah day and night, even though there is no food or clothing in his house, and his children and the members of his household cry out to him: Provide us with our support and maintenance. And he does not heed them at all, or listen to their cries.
The principal safeguard is seclusion, that you should not, God forbid, leave the house, save for some exceedingly great need. ... And even in the synagogue you should be very short and leave quickly. It is better to pray at home, for in the synagogue it is impossible to be saved from envy, and from hearing vain talk and gossip, and one is punished for this.
