It was narrated that Ash-Sha'bi said:

"I heard Abu Juhaifah say: 'We asked 'Ali: "Do you have anything from the Messenger of Allah apart from the Qur'an?" He said: "No, by the One who splits the seeds and creates the soul, unless Allah gives a slave understanding of His Book, or except this sheet." I said: "What is in the sheet?" He said: "In it are (the regulations concerning) blood money and the freeing of captives and (the rule) that no Muslim should be killed for killing a disbeliever."

أَخْبَرَنَا مُحَمَّدُ بْنُ مَنْصُورٍ، قَالَ حَدَّثَنَا سُفْيَانُ، عَنْ مُطَرِّفِ بْنِ طَرِيفٍ، عَنِ الشَّعْبِيِّ، قَالَ سَمِعْتُ أَبَا جُحَيْفَةَ، يَقُولُ سَأَلْنَا عَلِيًّا فَقُلْنَا هَلْ عِنْدَكُمْ مِنْ رَسُولِ اللَّهِ ﷺ شَىْءٌ سِوَى الْقُرْآنِ فَقَالَ لاَ وَالَّذِي فَلَقَ الْحَبَّةَ وَبَرَأَ النَّسَمَةَ إِلاَّ أَنْ يُعْطِيَ اللَّهُ عَزَّ وَجَلَّ عَبْدًا فَهْمًا فِي كِتَابِهِ أَوْ مَا فِي هَذِهِ الصَّحِيفَةِ . قُلْتُ وَمَا فِي الصَّحِيفَةِ قَالَ فِيهَا " الْعَقْلُ وَفِكَاكُ الأَسِيرِ وَأَنْ لاَ يُقْتَلَ مُسْلِمٌ بِكَافِرٍ " .