Man needs many things for the upkeep of his existence and the development of human civilization, such as food, mounts, different types of industries, means of transportation etc. All these things exist in plenty in the present world. God has created the physical world in such a way that it is subservient and capable of being used by man for meeting his requirements. All these things are, so to say, signs from God. Though this declaration is in indirect language, it is in man’s interest to understand it, because when God resorts to direct communication, it will mark the end of the period allowed for the performance of good or bad deeds and not the beginning.