فقلتُ فالحجة في هذا لكَ الحُجَّةُ عليك في ألاَّ تَقْبَلَ خبَرَ الصَّادِق عَن منْ جَهِلْنا صدْقَه
The argument that works in your favor in this case works against you otherwise, I replied. You should decline to accept reports from a veracious person transmitted from someone else whose veracity is unknown