الكافي- ط الاسلامية, volume 6, page 227

2. Ali ibn Ibrahim has narrated from his father from Ibn Abi ‘Umayr from Hammad from al-Halabiy who has said the following: “I once asked abu ‘Abd Allah (a.s.), about slaughtering with (sharp) piece of wood, reeds and stone. He (the Imam) said that Ali ibn abu Talib (a.s.), has said, ‘Without iron slaughtering is not proper.’”

Translation: Muhammad Sarwar·Thaqalayn link·The Arabic above is the original.

3. Muhammad ibn Yahya has narrated from Ahmad ibn Muhammad from Ali ibn al-Hakam from Sayf ibn ‘Amirah from abu Bakr al- Hadramiy who has said the following: “Abu ‘Abd Allah (a.s.), has said, ‘Animals that are not slaughtered with iron cannot be used for food.’”

Translation: Muhammad Sarwar·Thaqalayn link·The Arabic above is the original.

4. A number of our people have narrated from Ahmad ibn Muhammad from ibn Khalid from ‘Uthman ibn ‘Isa from Sama‘ah ibn Mehran who has said the following: “I once asked him (the Imam) (a.s.), about slaughtering. He (the Imam) said, ‘Slaughtering cannot properly be done without iron and ’Amir al-Mu’minin (a.s.), prohibited slaughtering without it.’”

Translation: Muhammad Sarwar·Thaqalayn link·The Arabic above is the original.