Sunan an-Nasa'i, Book 37, Hadith 134 (In-Book) ⓘ
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."
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 .
also referenced under: Hadith 4099 (Reference) & Volume 5, Book 37, Hadith 4104 (DarusSalam)