John Wesley explains Matthew 12, emphasizing the importance of mercy over sacrifice and the authority of Christ over the Sabbath. He illustrates how necessity can justify actions that may seem to transgress the law, as seen in David's example. Wesley highlights that true righteousness is about the heart and intentions, not merely following rituals. He warns against the dangers of blaspheming the Holy Spirit and stresses that one must be either for or against Christ. Ultimately, Wesley calls for a deeper understanding of faith that prioritizes love and mercy.