Deuteronomy 13:8 - Joseph Benson’s Commentary on the Old and New Testaments

Neither shall thine eye pity him The reason of the thing shows that two circumstances are implied: one is, that the seducer should be convicted by two sufficient witnesses before he should be put to death; the other, that the offender obstinately persisted in the defence of idolatry in spite of admonition; for who can doubt but a father, for instance, might save the life of his son, in case he brought him to timely repentance? Neither shalt thou conceal him That is, smother his fault, hide or protect his person; but shalt accuse him to the magistrate, and demand justice upon him.