أَخْبَرَنَا حُسَيْنُ بْنُ مَنْصُورٍ، قَالَ حَدَّثَنَا ابْنُ نُمَيْرٍ، قَالَ حَدَّثَنَا الأَعْمَشُ، عَنْ أَبِي إِسْحَاقَ، عَنْ عَاصِمِ بْنِ ضَمْرَةَ، عَنْ عَلِيٍّ، رضى الله عنه قَالَ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم ‏"‏ قَدْ عَفَوْتُ عَنِ الْخَيْلِ وَالرَّقِيقِ وَلَيْسَ فِيمَا دُونَ مِائَتَيْنِ زَكَاةٌ ‏"‏ ‏.‏

It was narrated that 'Ali, may Allah be pleased with him, said: "The Messenger of Allah said: 'I have exempted you from (having to pay Zakah on) houses and slaves, and there is no Zakah on less than two hundred (Dirhams)." Translation Not Available

Book Ref: Sunan An Nisai Book 23 Hadith 2478
Web Ref:  Sunan An Nisai Vol 3 Book 23 Hadith 2480