Musnad Ahmad 3:92

Mu'awiyah ibn 'Amr narrated to us, Za'idah narrated to us, from 'Asim, from Shaqiq, who said: 'Abd al-Rahman ibn 'Awf met al-Walid ibn 'Uqbah, and al-Walid said to him: "What is the matter with me that I see you have distanced yourself from the Commander of the Faithful, 'Uthman?" 'Abd al-Rahman said to him: "Inform him that I did not flee on the day of 'Aynayn" — 'Asim said: "He means the day of Uhud" — "and I did not stay behind on the day of Badr, and I have not abandoned the Sunnah of 'Umar." He said: So he went and informed 'Uthman of that. He said: So he said: "As for his saying that I fled on the day of 'Aynayn, how can he reproach me for a sin when Allah has already pardoned it? For He said: 'Indeed, those of you who turned back on the day the two armies met, it was only Satan who caused them to slip because of some what they had earned; but Allah has already pardoned them' [Al 'Imran: 155]. And as for his saying that I stayed behind on the day of Badr, I was nursing Ruqayyah, the daughter of the Messenger of Allah (peace and blessings of Allah be upon him), until she died, and the Messenger of Allah (peace and blessings of Allah be upon him) had assigned me my share [of the spoils], and whoever the Messenger of Allah (peace and blessings of Allah be upon him) assigned a share to, he has indeed witnessed [the battle]. And as for his saying that I have not abandoned the Sunnah of 'Umar, I am not capable of it, nor is he. So go to him and tell him that."