Abu Hurayrah (may Allah be pleased with him) reported that he heard the Messenger of Allah (may Allah's peace and blessings be upon him) say: "The testimony of a Bedouin against a city dweller is not permissible.''
شرح الحديث :
This Hadīth illustrates one of the impediments to the acceptance of testimony; a desert dweller may not testify concerning a city or town dweller. The reason is that the testimony is doubtful; for why should a person who lives away and does not usually know the situation in town testify to something that happens there? Also, the reason could be that the desert people are usually rough and ignorant, and they might not take the testimony seriously, for they do not know the standards of preserving people's rights. This was the view of Imām Mālik and Imām Ahmad. However, the majority of scholars held that the testimony of desert people is accepted due to the general indications of evidence. They interpreted this Hadīth to be referring to the desert people whose trustworthiness and reliability is not verified.