Al-Kāfi - Volume 6 > Slaughtering by the People of the Book
Hadith #8

عَلِيُّ بْنُ إِبْرَاهِيمَ عَنْ أَبِيهِ عَنِ ابْنِ أَبِي عُمَيْرٍ عَنِ الْحُسَيْنِ الْأَحْمَسِيِّ عَنْ أَبِي عَبْدِ اللَّهِ ( عليه السلام ) قَالَ قَالَ لَهُ رَجُلٌ أَصْلَحَكَ اللَّهُ إِنَّ لَنَا جَاراً قَصَّاباً فَيَجِي‏ءُ بِيَهُودِيٍّ فَيَذْبَحُ لَهُ حَتَّى يَشْتَرِيَ مِنْهُ الْيَهُودُ فَقَالَ لَا تَأْكُلْ مِنْ ذَبِيحَتِهِ وَ لَا تَشْتَرِ مِنْهُ .

8. Ali ibn Ibrahim has narrated from his father from ibn abu ‘ Umayr from al-Husayn al-Ahmasiy who has said the following: “Once a man said to ‘Abd Allah, ‘Alayhi al-Salam, ‘I pray to Allah to keep you well, we have a neighbor who is a butcher and he brings Jews who slaughter for him so that Jews can buy from him.’ He (the Imam) said, ‘Do not use for food what he sells and do not buy from him.’”