The only preserved divine revelation was Quran

حَدَّثَنَا صَدَقَةُ بْنُ الْفَضْلِ، أَخْبَرَنَا ابْنُ عُيَيْنَةَ، حَدَّثَنَا مُطَرِّفٌ، قَالَ سَمِعْتُ الشَّعْبِيَّ، قَالَ سَمِعْتُ أَبَا جُحَيْفَةَ، قَالَ سَأَلْتُ عَلِيًّا ـ رضى الله عنه ـ هَلْ عِنْدَكُمْ شَىْءٌ مَا لَيْسَ فِي الْقُرْآنِ وَقَالَ مَرَّةً مَا لَيْسَ عِنْدَ النَّاسِ فَقَالَ وَالَّذِي فَلَقَ الْحَبَّ وَبَرَأَ النَّسَمَةَ مَا عِنْدَنَا إِلاَّ مَا فِي الْقُرْآنِ، إِلاَّ فَهْمًا يُعْطَى رَجُلٌ فِي كِتَابِهِ، وَمَا فِي الصَّحِيفَةِ‏.‏ قُلْتُ وَمَا فِي الصَّحِيفَةِ قَالَ الْعَقْلُ، وَفِكَاكُ الأَسِيرِ، وَأَنْ لاَ يُقْتَلَ مُسْلِمٌ بِكَافِرٍ‏.‏

Narrated Ash-Shubi: I heard Abu Juhaifa saying, "I asked Ali 'Is there anything that is not in the Quran?' {Once he said, what is not with the people?} Ali replied, 'By Him Who made the grain split (germinate) and created the soul, we have nothing except what is in the Qur'an. The only understanding He gives man is in His book Book and what is written in this paper.' I asked, 'What is written in this paper?' He replied, 'Al-Aql (the regulation of Diya), about the ransom of captives, and the Judgment that a Muslim should not be killed in Qisas (equality in punishment) for killing a disbeliever."

Sahih al-Bukhari 6903 https://sunnah.com/bukhari:6903