Likutei Etzot, Money and Livelihood 23

The main lack of livelihood, which has diminished in these generations, is only because of slaughterers who are not worthy. For a worthy slaughterer feeds and sustains Israel, and he elevates the reincarnated soul of the living creature through the blessing that he recites over the slaughter. But when the slaughterer is not worthy, and even at the time of the blessing he thinks a defiled thought and is not present at the time of the blessing, then when he stands with the knife to slaughter the animal, he stands like a murderer of souls, and the soul of the animal is in pain and cries out with a bitter voice, for he does not elevate the reincarnated soul. On the contrary, he brings the soul down from its level and it finds no rest for the sole of its foot. Woe to this slaughterer, woe to the soul, for he has killed the soul and handed it over into the hand of its enemies. Through this livelihood is diminished, and the little livelihood must be drawn down with great trouble and toil. Through these slaughterers the soul is subdued before the body and materiality, and the desires of the body etc. grow stronger. But through worthy slaughterers the soul is elevated, and the body and materiality are subdued and nullified, the aspect of the animal, foolishness and darkness, the aspect of death, forgetfulness and judgment, the aspect of external wisdoms. And the soul and the form are elevated, the aspect of man, wisdom, light, life, memory and lovingkindness, the aspect of the wisdom of the Torah. Through this livelihood is drawn down in great abundance, as mentioned above (Likutei Moharan I, Torah 37, §6).