Origen

“ For it is not right that the dwelling-place of the rational soul should be cast aside anywhere without honour, like the carcases of brute beasts; and so much the more when we believe that the respect paid to the body redounds to the honour of the person who received from God a soul which has nobly employed the organs of the body in which it resided. ”

“ We do not believe that souls pass from one body to another, and that they may descend so low as to enter the bodies of the brutes. If we abstain at times from eating the flesh of animals, it is evidently, therefore, not for the same reason as Pythagoras ”

“ For that which is offered to idols is sacrificed to demons, and a man of God must not join the table of demons. As to things strangled, we are forbidden by Scripture to partake of them, because the blood is still in them; and blood, especially the odour arising from blood, is said to be the food of demons. Perhaps, then, if we were to eat of strangled animals, we might have such spirits feeding along with us. And the reason which forbids the use of strangled animals for food is also applicable to the use of blood. ”