This research was targeted toward the analysis of the monotheistic approach of Prophet Mohammad to the nature of illness in order to define the basics and principles of this approach and its effects on patient’s psych and therapeutic process. This paper aims to present a pattern for the promotion of patients’ spirituality and utilization of the illness as an optimal opportunity to help the therapeutic process. This is a concept analysis. The results of this study showed that the Prophet Mohammad had adopted a monotheistic approach to the illness that is attributable to the will of Allah. Allah causes the diseases to purify and promote human beings. The illness draws human attention to the instability of the world and causes human beings to do good deeds in the worldly life in order to earn reward in the hereafter. Therefore, the believers tolerate the illness with the hope of Allah’s reward. Finally, the believers become different from the unbelievers in two aspects: (a) the believers recover from the disease and gain greater faith and purity than unbelievers and (b) they do not recover and die like the unbelievers. However, the believers receive the divine blessings. As stated in the prophetic narrations, the believers must not ask for the disease from Allah, but they should try to recover from the disease. If they get sick, they should follow the above-mentioned approach. The obtained data of this paper can be used not only for spiritual growth in the event of disease but also for the recovery and pain relief.