Mere formalism in worship is a danger that the church of Christ has had to fight in every age. It is so easy for church members to become accustomed to the practice of worship such that it becomes a mere habit. Malachi was used in a mighty way to warn the church of his day about the evil of worshiping God outwardly rather than from the heart. In nine lessons, the author presents this study as a means to open the minds and hearts of believers to the treasures of wisdom in the prophecy of Malachi, which has special significance in being the last book of the Old Testament.