Musnad Abu Ya'la al-Mawsili 3:134

'Ubayd Allah ibn 'Umar al-Jushami and Abu Khaythama narrated to us, they said: Sufyan narrated to us, from 'Amr ibn Dinar, from al-Hasan ibn Muhammad, from 'Ubayd Allah ibn Abi Rafi', the scribe of 'Ali, who said: I heard 'Ali saying: The Messenger of Allah (ﷺ) sent me, al-Zubayr, and al-Miqdad, and said: "Go until you reach Rawdat Khakh, for there is a woman riding a camel there, and with her is a letter, so take it from her." We set off, racing our horses, until we reached the meadow. We found the woman, so we said: "Produce the letter." She said: "I have no letter with me." We said: "You will either produce the letter, or we will search your clothes." So she took it out from her hair braids. We brought it to the Prophet (ﷺ), and it contained: "From Hatib ibn Abi Balta'a to the people of Makkah," informing them of some of the affairs of the Messenger of Allah (ﷺ). The Messenger of Allah (ﷺ) summoned Hatib and said: "What is this?" He said: "Do not be hasty with me. I was merely an ally among the Quraysh and not one of their own kin, and there is no one among your companions except that he has someone in Makkah to protect his family and property, except for me. So I wanted to do them a favor, and I did not do it out of disbelief, nor apostasy from my religion, nor out of satisfaction with disbelief after Islam." The Messenger of Allah (ﷺ) said: "He has told you the truth." 'Umar said: "Let me, O Messenger of Allah, strike the neck of this hypocrite." He (the Prophet) said to him: "He has witnessed Badr. And what do you know? Perhaps Allah looked upon the people of Badr and said: 'Do what you wish, for I have forgiven you.'"