John Wesley on Acts 13:39

Every one that believeth is justified from all things - Has the actual forgiveness of all his sins, at the very time of his believing; from which ye could not be justified - Not only ye cannot now; but ye never could. For it afforded no expiation for presumptuous sins. By the law of Moses - The whole Mosaic institution! The division of the law into moral and ceremonial was not so common among the Jews, as it is among us. Nor does the apostle here consider it at all: but Moses and Christ are opposed to each other.