Scribes and Pharisees - See the notes at Matthew 3:7.
Moses’ seat - Moses was the great legislator of the Jews. By him the Law was given. The office of explaining that Law among the Jews devolved on the scribes and Pharisees. In the synagogues they sat while expounding the Law, and rose when they read it. By “sitting in the seat of Moses” we are to understand authority to teach the Law; or, as he taught the nation by giving the Law, so they taught it by explaining it.