Musannaf Ibn Abi Shayba 13:1973

Abu Bakr narrated to us, he said: Ibn Fudayl narrated to us, from Ibn Shubruma, from al-Sha'bi, he said: I asked him about a man who had a debt owed to him by another man, so he brought two witnesses, and one of the witnesses became a judge. Al-Sha'bi said: A man came to Shurayh to dispute, and I was sitting with him. The other man came against him with a witness, then he said to Shurayh: "Will you testify for me?" Shurayh said: "Go to the Amir (governor) so that I may testify for you."