"If one should give me a dish of sand and tell me there were particles of iron in it, I might look for them with my eyes, and search for them with my clumsy fingers, and be unable to detect them; but let me take a magnet and sweep through it, and how it would draw to itself the almost invisible particles by the mere power of attraction! The unthankful heart, like my finger in the sand, discovers no mercies: but let the thankful heart sweep through the day; and, as the magnet finds the iron, so it will find, in every hour, some heavenly blessings; only the iron in God's sand is gold."—Oliver Wendall Holmes