“When ... your natural desire to eat meat asserts itself, so that you say, 'I wish to eat meat,' you may eat as much meat as you wish.”
All that is created in this world contains in itself a mixture of good and bad. Therefore, the purpose of each creation is to improve on its physical nature and to progress spiritually. Human souls may be reincarnated in the bodies of domestic animals, wild animals, and birds. The kosher slaughterer, or the shochet, needs to have these two intentions in mind: to improve the physical nature of the world by sweetening the judgments found in it, and to complete the punishment of this reincarnation, preparing the soul to come into the body of a human at the time of birth, as other human souls born to proper people.
When the shochet sharpens his knife on the sharpening block, to remove a dent, and at the time when he examines his knife for dents, he should have in mind that dent (פגם) has the value of 123, or 3 times the word מא, and the value of this word, 41, corresponds to the number of letters in the name of God, its expansion, and the expansion of the expansion. All these names have the aspects of judgment in them, and the shochet should have the intention to sweeten these judgments. He then converts them into the names of 42 letters, which are all mercy.
Art: Jacopo Bassano - Animals Entering the Ark