Narrated Qays ibn Abbad :

I and Ashtar went to Ali and said to him: Did the Messenger of Allah ﷺ give you any instruction about anything for which he did not give any instruction to the people in general?

He said: No, except what is contained in this document of mine. Musaddad said: He then took out a document. Ahmad said: A document from the sheath of his sword.

It contained: The lives of all Muslims are equal; they are one hand against others; the lowliest of them can guarantee their protection. Beware, a Muslim must not be killed for an infidel, nor must one who has been given a covenant be killed while his covenant holds. If anyone introduces an innovation, he will be responsible for it. If anyone introduces an innovation or gives shelter to a man who introduces an innovation (in religion), he is cursed by Allah, by His angels, and by all the people.

Musaddad said: Ibn AbuUrubah's version has: He took out a document.

حَدَّثَنَا أَحْمَدُ بْنُ حَنْبَلٍ، وَمُسَدَّدٌ، قَالاَ حَدَّثَنَا يَحْيَى بْنُ سَعِيدٍ، أَخْبَرَنَا سَعِيدُ بْنُ أَبِي عَرُوبَةَ، عَنْ قَتَادَةَ، عَنِ الْحَسَنِ، عَنْ قَيْسِ بْنِ عَبَّادٍ، قَالَ انْطَلَقْتُ أَنَا وَالأَشْتَرُ، إِلَى عَلِيٍّ عَلَيْهِ السَّلاَمُ فَقُلْنَا هَلْ عَهِدَ إِلَيْكَ رَسُولُ اللَّهِ ﷺ شَيْئًا لَمْ يَعْهَدْهُ إِلَى النَّاسِ عَامَّةً قَالَ لاَ إِلاَّ مَا فِي كِتَابِي هَذَا - قَالَ مُسَدَّدٌ قَالَ - فَأَخْرَجَ كِتَابًا - وَقَالَ أَحْمَدُ كِتَابًا مِنْ قِرَابِ سَيْفِهِ - فَإِذَا فِيهِ " الْمُؤْمِنُونَ تَكَافَأُ دِمَاؤُهُمْ وَهُمْ يَدٌ عَلَى مَنْ سِوَاهُمْ وَيَسْعَى بِذِمَّتِهِمْ أَدْنَاهُمْ أَلاَ لاَ يُقْتَلُ مُؤْمِنٌ بِكَافِرٍ وَلاَ ذُو عَهْدٍ فِي عَهْدِهِ مَنْ أَحْدَثَ حَدَثًا فَعَلَى نَفْسِهِ وَمَنْ أَحْدَثَ حَدَثًا أَوْ آوَى مُحْدِثًا فَعَلَيْهِ لَعْنَةُ اللَّهِ وَالْمَلاَئِكَةِ وَالنَّاسِ أَجْمَعِينَ " . قَالَ مُسَدَّدٌ عَنِ ابْنِ أَبِي عَرُوبَةَ فَأَخْرَجَ كِتَابًا .