ENOfficial
Abu Huraira reported God's Messenger as saying, “The testimony of a nomadic Arab against a townsman is not allowable." Abu Dawud and Ibn Majah transmitted it.
Source: sunnah.com
Other translations
Arabic
وَعَنْ أَبِي هُرَيْرَةَ عَنْ رَسُولِ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ قَالَ: «لَا تَجُوزُ شَهَادَةُ بَدَوِيٍّ عَلَى صَاحِبِ قَرْيَةٍ» . رَوَاهُ أَبُو دَاوُدَ وَابْنُ مَاجَه
sunnah.com