A learned man is expected to live in the light of his knowledge, so that everything he does or says will itself constitute Torah.
It was said of the scholar who transgressed:
"His Torah was but lip service," since true Torah must be reflected in personal behavior as in study.
These were not merely abstract moral rules but very practical halakhic precepts.
The codifiers also regarded them as such and determined that a man, however erudite,
whose conduct was contemptible, could not be respected for his learning but should be condemned and despised.
It is often related in the Talmud that learned people of dubious character were punished, chastised, or excommunicated.
Thus scholarship is not merely an intellectual standard but encompasses the entire personality, the man becoming the symbol of Torah, his whole essence synonymous with it.
We can therefore understand the eagerness to study the deeds and conversations of
scholars and to learn from them, given the assumption that anything done or said by the scholar can serve as a guide to others.
–Rabbi Adin Steinsaltz
From The Essential Talmud, “What is a scholar?” by Rabbi Adin Steinsaltz