Matthew Henry's Concise Commentary

15:22-29 Though ignorance will in a degree excuse, it will not justify those who might have known their Lord's will, yet did it not. David prayed to be cleansed from his secret faults, those sins which he himself was not aware of. Sins committed ignorantly, shall be forgiven through Christ the great Sacrifice, who, when he offered up himself once for all upon the cross, seemed to explain one part of the intention of his offering, in that prayer, Father, forgive them, for they know not what they do. It looked favourably upon the Gentiles, that this law of atoning for sins of ignorance, is expressly made to extend to those who were strangers to Israel.