Sunan an-Nasa'i, Volume 6, Book 51, Hadith 5727 (DarusSalam)

Abu Raja' said: "I asked Al-Hasan about At-Tila' (thickened grape juice) that has been reduced to half. He said: 'Do not drink it.'"

أَخْبَرَنَا سُوَيْدٌ، قَالَ أَنْبَأَنَا عَبْدُ اللَّهِ، عَنْ يَزِيدَ بْنِ زُرَيْعٍ، قَالَ حَدَّثَنَا أَبُو رَجَاءٍ، قَالَ سَأَلْتُ الْحَسَنَ عَنِ الطِّلاَءِ الْمُنَصَّفِ، فَقَالَ لاَ تَشْرَبْهُ ‏.‏

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