Consider the human eye. Though it hath the faculty of perceiving all created things, yet the slightest impediment may so obstruct its vision as to deprive it of the power of discerning any object whatsoever. Magnified be the name of Him Who hath created, and is the Cause of, these causes, Who hath ordained that every change and variation in the world of being be made dependent upon them. Every created thing in the whole universe is but a door leading into His knowledge, a sign of His sovereignty, a revelation of His names, a symbol of His majesty, a token of His power, a means of admittance into His straight Path.… 