The Book of Fighting [The Prohibition of Bloodshed]
37/26. Chapter:
The One Who Unsheathes His Sword and Starts to Strike the People With it
Sunan an-Nasai
أَخْبَرَنَا أَبُو دَاوُدَ، قَالَ حَدَّثَنَا أَبُو عَاصِمٍ، عَنِ ابْنِ جُرَيْجٍ، عَنِ ابْنِ طَاوُسٍ، عَنْ أَبِيهِ، عَنِ ابْنِ الزُّبَيْرِ، قَالَ مَنْ رَفَعَ السِّلاَحَ ثُمَّ وَضَعَهُ فَدَمُهُ هَدَرٌ .
It was narrated that Ibn Az-Zubair said: "Whoever wields a weapon and starts to strike (the people) with it, it is permissible to shed his blood."
Reference : Sunan an-Nasa'i 4099In-book reference : Book 37, Hadith 134English translation : Vol. 5, Book 37, Hadith 4104