{But be not ye called Rabbi} (humeis de m(8820)kl(8874)h(8874)e
Rabbei). An apparent aside to the disciples. Note the emphatic
position of humeis. Some even regard verses  8-10  as a later
addition and not part of this address to the Pharisees, but the
apostles were present. Euthymius Zigabenus says: "Do not seek to
be called (ingressive aorist subjunctive), if others call you
this it will not be your fault." This is not far from the
Master's meaning. Rabbi means "my great one," "my Master,"
apparently a comparatively new title in Christ's time.