32. The alternation of the night and day also is one of those realities which man does not regard as worthy of much attention only because it is a phenomenon of daily occurrence and experience; whereas if he considers how the day passes and how the night falls, and what is the wisdom in the passing of the day and in the falling of the night, he will himself realize that this is an obvious sign of the existence of an All-Powerful and All-Wise Allah and of His being One and only One. The day cannot pass and the night cannot fall until the sun hides from the earth. The great regularity which is found in the alternation of the day and night was not possible unless the sun and the earth were bound in one and the same relentless system. Then the deep relationship which exists between the alternation of the day and night and the other creations on the earth clearly points to the fact that this system has been established deliberately by a Being with perfect wisdom. The existence on the earth, of the men and animals and vegetation, and even of water and air and different minerals, is in fact, the result of placing the earth at a particular distance from the sun, with the arrangement that the different parts of the earth should go on successively coming before the sun and hiding from it at definite intervals. If the distance of the earth from the sun had been a little longer, or a little shorter, or there had been a perpetual night on one side of it and a perpetual day on the other, or the alternation of the day and night had been much faster or much slower, or sometimes the day had appeared suddenly and sometimes the night without any system, no life could be possible on this planet, and even the form and appearance of the inorganic substances would have been much different from what it is now. If the hearts are not blinded, one can clearly perceive in this system the working of a God, Who willed to bring into being this particular kind of creation on the earth and then established relevance, harmonies and relationships between the earth and the sun precisely in accordance with its needs and requirements. If a person regards the concept of the existence of God and His Unity as far removed from reason, he should think for himself and see how much farther removed should it be from reason to ascribe this wonderful creation to many gods, or to think that all this has happened automatically under some deaf and blind law of nature. When a person who can accept without question these latter unreasonable explanations, only on the basis of conjecture and speculation, says that the existence of a system and wisdom and purpose is not a sufficient proof of the existence of God, it becomes difficult for us to believe whether such a person really feels the need and necessity of a rational proof, sufficient or insufficient in any degree whatever, for accepting any concept of creed in the world.