Jesus instructed the people to obey God’s commands given through their hypocritical teachers, not because of their conduct, but because they sit in Moses’ seat, they hold an office of authority, ordained by God.
Normally people estimate greatness by how many people serve and honor them. Jesus reminded His followers that in His kingdom it should be different and that we should estimate greatness by how we serve and honor others. The proud always be humiliated but the humble exalted.