Natural pearls form when an irritant - usually a parasite and not the proverbial grain of sand - works its way into an oyster, mussel, or clam. As a defense mechanism, a fluid is used to coat the irritant. Layer upon layer of this coating, called 'nacre', is deposited until a lustrous pearl is formed.
What a challenge to me when those irritating people and down right parasites get under my skin-- I know that I could never be like that to others :). Instead of responding in anger, nursing resentment or retaliating in hurt and shame, I seek to cover and coat those irritants with love. Our inner character -being shaped by God- and our willing, gracious responses to those around us are of eternal and cosmic value. This is the pearl of great price.