Sayyiduna Anas bin Malik (may Allah be pleased with him) said: We besieged Tustar, and al-Hurmuzan came down on the judgement of Sayyiduna Umar (may Allah be pleased with him). I set off with him to Sayyiduna Umar (may Allah be pleased with him). When we reached him, Sayyiduna Umar (may Allah be pleased with him) said: Speak. He asked: Shall I speak the speech of a living man or the speech of a dead man? Sayyiduna Umar (may Allah be pleased with him) said: Speak, there is no harm. He said: O community of Arabs, as long as Allah left (matters) between us and you, we used to dominate you, kill you and seize your wealth; then when Allah was with you, we had no power left. Sayyiduna Umar (may Allah be pleased with him) said: What do you say? I said: O Commander of the Believers! I have left behind me a great many enemies and fierce strength; if you kill him, the people will despair of life and their resistance will become fiercer. Sayyiduna Umar (may Allah be pleased with him) said: Shall I spare the killer of al-Bara' bin Malik and Majza'ah bin Thawr (may Allah be pleased with them both)? When I feared that he would indeed kill him, I said: There is no way for you to kill him; you have already said to him: Speak, there is no harm. Sayyiduna Umar (may Allah be pleased with him) said: You have taken a bribe and received something from him. I said: By Allah! I have neither taken a bribe nor received anything from him. Sayyiduna Umar (may Allah be pleased with him) said: Either you bring me someone else to testify to this, or I will certainly punish you. He said: I went out and met Sayyiduna al-Zubayr bin al-Awwam (may Allah be pleased with him), and he testified along with me. Sayyiduna Umar (may Allah be pleased with him) held back, and al-Hurmuzan became a Muslim, and a stipend was fixed for him.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب السير / 18183