Verse 21. Thou therefore, etc. he who is a teacher of others may be expected to be learned himself. They ought to be found to be possessed of superior knowledge; and by this question the apostle impliedly reproves them for their ignorance. The form of a question is chosen because it conveys the truth with greater force. He puts the question as if it were undeniable that they were grossly ignorant. Comp. Mt 23:3, "They say, and do not," etc.

That preachest. This word means to proclaim in any manner, whether in the synagogue, or in any place of public teaching.

Dost thou steal? It cannot be proved, perhaps, that the Jews were extensively guilty of this crime. It is introduced partly, no doubt, to make the inconsistency of their conduct more apparent. We expect a man to set an example of what he means by his public instruction.

{d} "Thou therefore which" Mt 23:3