Abu Dawud Book 18, Hadith Number 3598.

Narated By AbuMusa al-Ash’ari : Ash-Sha’bi said: A Muslim was about to die at Daquqa’, but he did not find any Muslim to call him for witness to his will. So he called two men of the people of the Book for witness. Then they came to Kufah, and approaching AbuMusa al-Ash’ari they informed him (about his) will. They brought his inheritance and will. Al-Ash’ari said: This is an incident (like) which happened in the time of the Apostle of Allah (PBUH) and never occurred after him. So he made them to swear by Allah after the afternoon prayer to the effect that they had not misappropriated, nor told a lie, nor changed, nor concealed, nor altered, and that it was the will of the man and his inheritance. He then executed their witness.