J.R. Miller emphasizes the sinful nature of bad temper, arguing that it is an infirmity that should not be excused or tolerated. He highlights the practical advantages of maintaining good temper, such as improving one's reputation, enhancing personal comfort, and fostering meaningful friendships. Miller asserts that good temper is essential for true manliness, aligning with Christ's example of meekness and self-control. He encourages striving for self-mastery, as it leads to a more fulfilling and noble life. Ultimately, he reminds us that with Christ's help, we can achieve victory over our tempers and embody the qualities of love and patience.