Uthman bin Mawhab reported,

A man came to perform the pilgrimage to the House. He saw a group of people sitting and asked, "Who are these people sitting here?"They replied, "These are Quraysh."He asked, "Who is the elder among them?"They said, "Ibn Umar."So he came to him and said, "I want to ask you about something. Will you answer me?"Ibn Umar said, "Yes."The man said, "I adjure you by the sanctity of this House, do you know that Uthman bin Affan fled on the day of Uhud?"Ibn Umar replied, "Yes."The man asked, "And do you know that he was absent from Badr and did not take part in it?"He replied, "Yes."The man asked, "And do you know that he stayed back from the Pledge of Ridwan and did not witness it?"He replied, "Yes."The man exclaimed, "Allahu Akbar!"Ibn Umar said, "Come, let me inform you and clarify for you what you have asked about. As for his flight on the day of Uhud, I bear witness that Allah has pardoned him for that. As for his absence from Badr, he was married to the daughter of the Messenger of Allah ﷺ and she was ill, so the Prophet ﷺ said to him, 'You will have the reward of a man who witnessed Badr and his share of the spoils.' As for his absence from the Pledge of Ridwan, if there had been anyone in the heart of Makkah more honored than Uthman bin Affan, the Prophet would have sent him in his place. So he sent Uthman, and the Pledge of Ridwan took place after Uthman had gone to Makkah. The Prophet ﷺ said, holding out his right hand, 'This is the hand of Uthman,' and he struck it upon his other hand and said, 'This is on behalf of Uthman.' Now take this answer with you and go."

عن عثمان بن موهب قال

جاء رجل حج البيت فرأى قوما جلوسا فقال: من هؤلاء القعود قالوا: هؤلاء قريش. قال: من الشيخ؟ قالوا: ابن عمر فأتاه فقال إني سائلك عن شيء أتحدثني؟ قال: أنشدك بحرمة هذا البيت أتعلم أن عثمان بن عفان فر يوم أحد؟ قال: نعم. قال: فتعلمه تغيب عن بدر فلم يشهدها؟ قال: نعم. قال: فتعلم أنه تخلف عن بيعة الرضوان فلم يشهدها؟ قال: نعم قال: فكبر. قال ابن عمر: تعال لأخبرك ولأبين لك عما سألتني عنه، أما فراره يوم أحد فأشهد أن الله عفا عنه، وأما تغيبه عن بدر فإنه كان تحته بنت رسول الله ﷺ وكانت مريضة، فقال له النبي ﷺ: إن لك أجر رجل ممن شهد بدرا وسهمه وأما تغيبه عن بيعة الرضوان فإنه لو كان أحد أعز ببطن مكة من عثمان بن عفان لبعثه مكانه، فبعث عثمان، وكان بيعة الرضوان بعد ما ذهب عثمان إلى مكة فقال النبي ﷺ بيده اليمنى: هذه يد عثمان، فضرب بها على يده فقال: هذه لعثمان، اذهب بهذا الآن معك.