John Lightfoot on Matthew 23:2

[In Moses' seat, &c.] this is to be understood rather of the legislative seat (or chair), than of the merely doctrinal: and Christ here asserts the authority of the magistrate, and persuadeth to obey him in lawful things.

Concerning the chairs of the Sanhedrim there is mention made in Bab. Succah: "There were at Alexandria seventy-one golden chairs, according to the number of the seventy-one elders of the great council." Concerning the authority of Moses and his vicegerent in the council, there is also mention in Sanhedrim: "The great council consisted of seventy-one elders. But whence was this number derived? From that place where it is said, 'Choose me out seventy men of the elders of Israel: and Moses was president over them.' Behold seventy-one!"

What is here observed by Galatinus from the signification of the aorist sat is too light and airy: "He saith, They sat and not, They sit, that he might plainly demonstrate, that their power was then ceased." But if we would be so curious to gather any thing from this aorist, we might very well transfer it to this sense rather: "The scribes and Pharisees, the worst of men, have long usurped Moses' seat; nevertheless, we ought to obey them, because, by the dispensation of the divine providence, they bear the chief magistracy."

Concerning their authority, thus Maimonides: "The great council of Jerusalem was the ground (the pillar and ground) of the traditional law, and the pillar of doctrine: whence proceeded statutes and judgments for all Israel. And concerning them the law asserts this very thing, saying, 'According to the sentence of the law which they shall teach thee.' Whosoever, therefore, believes Moses our master and his law, is bound to rely upon them for the things of the law."

Christ teacheth, that they were not to be esteemed as oracles, but as magistrates.