from The Conference of the Birds (Mantiq ut-Tair in Arabic) by Farid ud-Din Attar, composed in the second half of the twelfth century A.D.
Prayer of a Madman
A Sufi, an idiot of God, was tormented by children who threw stones at him. At last he took refuge in a corner of a dwelling. But at that moment it began to hail and the hailstones came through an open skylight and fell on his head. The man took the hail for pebbles and began to stretch out his tongue and insult the children, whom he imagined were throwing them, for the house was dark. At length he discovered that the pebbles were only hailstones, and he was sorry and prayed: 'Oh God, it was because the house was dark that I have sinned with my tongue.'
If you understand the motives of those who are in darkness, you will, no doubt, forgive them.*
*How I wish I will one day take this lesson into my heart...Insh'Allah