وَالْقَمَرَ قَدَّرْنَاهُ مَنَازِلَ حَتَّىٰ عَادَ كَالْعُرْجُونِ الْقَدِيمِ (39)
(36:39) We have appointed stages for the moon till it returns in the shape of a dry old branch of palm-tree. *34
*34) That is, the phases of the moon go on changing throughout the month. 1t begins as a crescent, then goes on waxing every. day till it becomes the full moon on the 14th of the month. Then it starts waning every day till at last it returns to its original shape of the crescent. The same has been happening for millions of years with perfect regularity, and no change has ever occurred in the phases of the moon. That is why one can always calculate and find out exactly in what phase the moon will be on a particular day. If the movement of the moon had not been bound in a system, estimation of its phases would not have been possible.