The Apostle Paul
Romans 2:21BSB·traditional attribution

you, then, who teach others, do you not teach yourself? You who preach against stealing, do you steal?

John Calvin Reformed @genevareformer

21. Thou, who then teachest another, teachest not thyself, etc. This clause, and those which follow, are commonly put in an interrogatory form, that is, as questions: but some, as Theophylact, Erasmus and Luther, have rendered the clauses in the form here adopted. There is no difference in the meaning.

Matthew Henry Presbyterian @wholebiblehenry

In the latter part of the chapter the apostle directs his discourse more closely to the Jews, and shows what sins they were guilty of, notwithstanding their profession and vain pretensions. He had said (Rom 2:13) that not the hearers but the doers of the law are justified; and he here applies that great truth to the Jews. Observe, I.

Commenting on Romans 2:17-29

John Gill Reformed Baptist @doctorgill

Thou that makest thy boast of the law,.... Of their having it, which other nations had not; of their knowledge of it, which many of their own people were without, or had but a small share of; and of their keeping of it even to perfection: through breaking of the law dishonourest thou God?