1,016. Despising Torah Scholars
144:4 It is a great sin to denigrate or despise Torah scholars. Jerusalem wasn't destroyed until they despised the Sages as per II Chronicles 36:16, "They mocked the messengers of G-d, despised His words, and scoffed at His prophets," meaning that they despised those who teach His words. Similarly, Leviticus 26:15, "If you despise My statutes" means "If you despise the teachers of My statutes." Whoever despises the Sages has no share in the Next World. This is included in those who despise the word of G-d (Numbers 15:31). It's forbidden to use a scholar as one's attendant.
144:5 If a Torah scholar has merchandise to sell, we do not permit anyone else to sell the same merchandise until he has done so. This is only if there isn't a non-Jew present who is selling such merchandise. If there is a non-Jew present selling such merchandise, we do not restrict other Jews from selling because the scholar will have to lower his prices to compete anyway.