Man is an independent being. He has the wisdom to distinguish between good and bad, and make inferences from his continued sustenance on earth. When he falls ill, he finds that there is an abundance of resources from which to derive remedies. But then, man observes that in spite of all his apparent freedom, he is helpless in the face of death. He dies at the end of his allotted lifespan. All these factors can be caused by none other than the one and only God. Then, how can it be legitimate and proper to worship anybody except Him alone? Moreover, a man should be extremely serious and sincere in this matter, because these factors also indicate that whatever God does is in preparation for the day when man will be called before Him to give an account of himself. Death marks the beginning of this process when man will be judged by God on the basis of the performance of his deeds on earth.