R. Shimon b. Yochai says: It is written (Proverbs 27:7) "The sated soul will tread down a honeycomb": This is a Torah scholar who did not learn from the beginning; "but to the hungry soul all bitter is sweet": This is one who did learn (from the beginning). Variantly: "The sated soul will tread down a honeycomb (nofeth)": Just as a sieve extracts flour by itself, bran flour by itself, and wheat flour by itself, so, a Torah scholar sits and scrutinizes words of Torah and weighs them — This sage forbids, this sage permits; this sage rules unclean; this sage rules clean.