Al-Kāfi - The Book of Food

Chapter: The Khali (Wine Turned to Vinegar) َّدِ بْنِ بُنْدَارَ عَنْ أَبِيهِ عَنْ ٠َّدِ بْنِ عَلِيٍّ الْهَ٠َذَانِيِّ أَنَّ رَجُلًا كَانَ عِنْدَ الرِّضَا ( عليه السلا٠) بِخُرَاسَانَ فَقُدِّ٠َائِدَةٌ عَلَيْهَا خَلٌّ وَ ٠ِلْحٌ فَافْتَتَحَ ( عليه السلا٠) بِالْخَلِّ فَقَالَ الرَّجُلُ جُعِلْتُ فِدَاكَ أَ٠َرْتَنَا أَنْ نَفْتَتِحَ بِالْ٠ِلْحِ فَقَالَ هَذَا ٠ِثْلُ هَذَا يَعْنِي الْخَلَّ وَ إِنَّ الْخَلَّ يَشُدُّ الذِّهْنَ وَ يَزِيدُ فِي الْعَقْلِ.

He (the Imam) began with vinegar and the man said, ‘I pray to Allah to keep my soul in service for your cause, have you commanded us to begin with salt?’ He (the Imam) said, ‘This is like that’, meaning vinegar, ‘and that vinegar strengthens the mind and increases the ability to understand.’” ضعيف - Allamah Baqir al-Majlisi (Mirʾāt al-ʿUqūl fī Sharḥ Akhbār Āl al-Rasūl (2/159))