صحيح البخاري
Sahih Bukhari
كتاب الأحكام
The Book of Al-Ahkam (Judgements)
باب الشهادة تكون عند الحاكم فى ولايته القضاء أو قبل ذلك للخصم:
Chapter. If a judge has to witness in favour of a litigant when he is a judge or he had it before he became a judge (can he pass a judgement in his favour accordingly or should he refer the case to another judge before whom he would bear witness?).