Muhammad Ali, servant of the prophets, to Usbek in Erzerum
You always ask us questions that were asked a thousand times of our holy Prophet. Why do you not read the traditions of the scholars ?  Why do you not go to that pure spring of all understanding ? You would find all your doubts resolved.
Wretched man, who, ever confused by the things of earth, have never gazed fixedly on things of heaven, and will dream of the position of mullahs, not daring to embrace it or follow it.
You who are profane never enter into the secrets of the Eternal ; your lights are like the darkness of the abyss, and the reasoning of your minds is as the dust raised by your feet when the sun is at midday in the ardent month of Chahban. 
So it is that the zenith of your minds does not attain the nadir  of his who is least of the Immaums.  Your vain philosophy is the lightning that heralds the storm and the darkness ; you are in the midst of the tempest, and you drift with the winds.
It is quite easy to answer your objection. To do so, I need only tell you about what happened one day to our holy Prophet, when, tempted by Christians and tested by Jews, he confounded the ones and the others equally.
The Jew Abdias Ibesalon  asked him why God had forbidden us to eat the flesh of swine. It is not without reason, replied the Prophet : it is an impure animal, and of this I am going to convince you. He traced in mud on his hand the shape of a man  ; he threw it on the ground, and commanded it : Arise. At once a man arose, and said : I am Japheth, son of Noah. Did you have such white hair when you died ? the holy Prophet said to him. No, he replied ; but when you awakened me I thought the last judgment had come, and I was so terrified that my hair turned white on the spot.
Now tell me, said the Messenger of God to him, the whole story of Noah’s ark. Japheth obeyed, and related exactly everything that occurred in the first months, after which he spoke as follows :
We placed the excrement of all the animals on one side of the ark, which made it list so far that we feared for our lives, especially our wives, who wailed in great style. When our father Noah went to consult God, he was commanded to take the elephant and have him turn his head toward the side that was listing. The great animal made so much excrement that from it sprang a hog. Do you believe, Usbek, that since that time we have abstained from the hog, and have always considered it an impure animal ?
But as the hog every day agitated this excrement, such a stench arose in the ark that even he could not keep from sneezing, and out of his nose came a rat, which went about chewing up everything in its path ; and this became so unbearable to Noah that he thought it was time to consult God again. He commanded him to give the lion a blow on the forehead, which made him too sneeze, and expelled from his nose a cat. Do you believe that these animals too are impure ? What do you think ?
Therefore, when you do not perceive the reason for the impurity of certain things, that is because you are unaware of many others, and lack knowledge of what has passed between God, the angels, and men. You know not the story of eternity. You have not read the books that are written in heaven  ; what has been revealed to you about them is but a small part of the divine library ; and those who like us are more acquainted with it while they are in this life, are still in darkness and shadows. Adieu : Muhammad be in your heart.
Com this last day of the moon of Chahban 1711