John Wesley on Exodus 28:38

Aaron must have this upon his forehead, that he may bear the iniquity of the holy things, and that they may be accepted before the Lord - Herein he was a type of Christ, the great Mediator between God and man. Thro' him what is amiss in our services is pardoned: even this would be our ruin, if God should enter into judgment with us: but Christ our high priest bears this iniquity; bears it for us, so as to bear it from us. Thro' him likewise what is good is accepted; our persons, our performances are pleasing to God upon the account of Christ's intercession, and not otherwise. His being holiness to the Lord, recommends all those to the divine favour that believe in him. Having such a high priest, we come boldly to the throne of grace.