My uncle Anas bin An-Nadr was absent from the Battle of Badr. He said, "O Messenger of Allah ﷺ! I was absent from the first battle you fought against the pagans. (By Allah) if Allah gives me a chance to fight the pagans, no doubt. Allah will see how (bravely) I will fight." On the day of Uhud when the Muslims turned their backs and fled, he said, "O Allah! I apologize to You for what these (i.e. his companions) have done, and I denounce what these (i.e. the pagans) have done." Then he advanced and Saʿd bin Muʿadh met him. He said "O Saʿd bin Muʿadh ! By the Lord of An-Nadr, Paradise! I am smelling its aroma coming from before (the mountain of) Uhud," Later on Saʿd said, "O Allah's Apostle! I cannot achieve or do what he (i.e. Anas bin An-Nadr) did. We found more than eighty wounds by swords and arrows on his body. We found him dead and his body was mutilated so badly that none except his sister could recognize him by his fingers." We used to think that the following Verse was revealed concerning him and other men of his sort: "Among the believers are men who have been true to their covenant with Allah.........." (33.23) His sister Ar-Rubbaya' broke a front tooth of a woman and Messenger of Allah ﷺ ordered for retaliation. On that Anas (bin An-Nadr) said, "O Messenger of Allah ﷺ! By Him Who has sent you with the Truth, my sister's tooth shall not be broken." Then the opponents of Anas's sister accepted the compensation and gave up the claim of retaliation. So Messenger of Allah ﷺ said, "There are some people amongst Allah's slaves whose oaths are fulfilled by Allah when they take them."  

يَا رَسُولَ اللَّهِ غِبْتُ عَنْ أَوَّلِ قِتَالٍ قَاتَلْتَ الْمُشْرِكِينَ لَئِنِ اللَّهُ أَشْهَدَنِي قِتَالَ الْمُشْرِكِينَ لَيَرَيَنَّ اللَّهُ مَا أَصْنَعُ فَلَمَّا كَانَ يَوْمُ أُحُدٍ وَانْكَشَفَ الْمُسْلِمُونَ قَالَ اللَّهُمَّ إِنِّي أَعْتَذِرُ إِلَيْكَ مِمَّا صَنَعَ هَؤُلاَءِ يَعْنِي أَصْحَابَهُ وَأَبْرَأُ إِلَيْكَ مِمَّا صَنَعَ هَؤُلاَءِ يَعْنِي الْمُشْرِكِينَ ثُمَّ تَقَدَّمَ فَاسْتَقْبَلَهُ سَعْدُ بْنُ مُعَاذٍ فَقَالَ يَا سَعْدُ بْنَ مُعَاذٍ الْجَنَّةَ وَرَبِّ النَّضْرِ إِنِّي أَجِدُ رِيحَهَا مِنْ دُونِ أُحُدٍ قَالَ سَعْدٌ فَمَا اسْتَطَعْتُ يَا رَسُولَ اللَّهِ مَا صَنَعَ قَالَ أَنَسٌ فَوَجَدْنَا بِهِ بِضْعًا وَثَمَانِينَ ضَرْبَةً بِالسَّيْفِ أَوْ طَعْنَةً بِرُمْحٍ أَوْ رَمْيَةً بِسَهْمٍ وَوَجَدْنَاهُ قَدْ قُتِلَ وَقَدْ مَثَّلَ بِهِ الْمُشْرِكُونَ فَمَا عَرَفَهُ أَحَدٌ إِلاَّ أُخْتُهُ بِبَنَانِهِ قَالَ أَنَسٌ كُنَّا نَرَى أَوْ نَظُنُّ أَنَّ هَذِهِ الآيَةَ نَزَلَتْ فِيهِ وَفِي أَشْبَاهِهِ {مِنَ الْمُؤْمِنِينَ رِجَالٌ صَدَقُوا مَا عَاهَدُوا اللَّهَ عَلَيْهِ} إِلَى آخِرِ الآيَةِ وَقَالَ إِنَّ أُخْتَهُ وَهْىَ تُسَمَّى الرُّبَيِّعَ كَسَرَتْ ثَنِيَّةَ امْرَأَةٍ فَأَمَرَ رَسُولُ اللَّهِ ﷺ بِالْقِصَاصِ فَقَالَ أَنَسٌ يَا رَسُولَ اللَّهِ وَالَّذِي بَعَثَكَ بِالْحَقِّ لاَ تُكْسَرُ ثَنِيَّتُهَا فَرَضُوا بِالأَرْشِ وَتَرَكُوا الْقِصَاصَ فَقَالَ رَسُولُ اللَّهِ ﷺ إِنَّ مِنْ عِبَادِ اللَّهِ مَنْ لَوْ أَقْسَمَ عَلَى اللَّهِ لأَبَرَّهُ