A.B. Simpson emphasizes the profound connection between our spiritual and physical well-being, warning that even minor spiritual ailments can disrupt the flow of divine life within us. He highlights the detrimental effects of negative emotions such as worry, malice, and jealousy, which can drain our vitality more than physical exertion. Simpson advocates for cultivating a spirit of pleasantness, tranquility, and the peace of God, which are essential for maintaining health. He encourages listeners to guard against spiritual infections and to dedicate themselves to God's work to experience abundant life and strength.

Spiritual conditions are inseparably connected with our physical life. The flow of the divine life-currents may be interrupted by a little clot of blood; the vital current may leak out through a very small wound. If you want to keep the health of Christ, keep from all spiritual infections, from all heart wounds and irritations. One hour of worry will wear out more vitality than a week of work; one minute of malice or jealousy or envy will hurt more than a drink of poison. Pleasantness of spirit and joyousness of heart are essential to full health. Quietness of spirit, gentleness, tranquility and the peace of God that passes all understanding are worth more than all the sleeping pills in the country. We do not wonder that some people have poor health when we hear them talk for half an hour. They have enough dislikes, prejudices, doubts and fears to exhaust the strongest constitution. My friend, if you would maintain God's life and strength, keep out the things that kill it. Keep yourself for Him and for His work, and you will find enough and to spare.