Moses’ seat is a metaphorical expression representing the teaching and administrative authority of the synagogue leadership, scribes and Pharisees. Jesus condemns only the practice of the scribes and Pharisees and not their teaching. Matthew makes three points. The first is that they say but do not do, the second is that they burden while failing to act themselves and the third is that they act for the wrong reasons: to make an impression on others. “Phylacteries” is the term Matthew uses for the tephillin, which were small leather boxes containing portions of the Torah (Exod 13,1-16; Deut 6,4-9; 11,13-32) strapped to the forehead and arm during the recitation of prayers in literal obedience to Deut 6,8. The “tassels” were attached to the prayer shawls, and the most important seats in the synagogue refer to the place of honour at the front facing the congregation, occupied by teachers and respected leaders. The term “Rabbi” was a title of honour.
The point that the Gospel reading of today makes is that there must be a correlation between our words and our actions. It is easy to say, but difficult to do, it is easy to preach but difficult to practice. The way to ensure that there is a correlation between the two is to first do and then say, or better to let people hear not what you say but what you do.