"All food was lawful to the Children of Israel, except what Israel had made unlawful to himself before the Torah was revealed. Say, 'Bring the Torah and recite it' [i.e., read it], 'if you are truthful' in claiming that it contains what you mention [that] it has forbidden for you." Al-Hasan said: "What Israel had forbidden for himself was the meat of camels." Others said: "It was their milk."
﴿كُلُّ الطَّعَامِ كَانَ حِلا لِبَنِي إِسْرَائِيلَ إِلا مَا حَرَّمَ إِسْرَائِيلُ عَلَى نَفْسِهِ مِنْ قَبْلِ أَنْ تُنَزَّلَ التَّوْرَاةُ قُلْ فَأْتُوا بِالتَّوْرَاةِ فاتلوها﴾ [أَي: فاقرءوها] ﴿إِنْ كُنْتُمْ صَادِقِينَ﴾ أَن فِيهَا مَا تذكرُونَ [أَنه] حرمه عَلَيْكُم. قَالَ الْحسن: وَكَانَ الَّذِي حرم إِسْرَائِيل على نَفسه: لُحُوم الْإِبِل، وَقَالَ بَعضهم: أَلْبَانهَا.