Ibn Mas'ud said, "When the Messenger of Allah, may Allah bless him and grant him peace, divided the booty of Hunayn at Ji'rana, the people crowded up against him. Then the Messenger of Allah, may Allah bless him and grant him peace, said, 'Allah sent on of His slaves to a people and they rejected him and wounded him in the head. He wiped the blood from his brow, saying, "O Allah, forgive my people for they do not know."'"
Source: sunnah.com
Other translations
Arabic
حَدَّثَنَا مُسَدَّدٌ، قَالَ: حَدَّثَنَا حَمَّادُ بْنُ زَيْدٍ، عَنْ عَاصِمِ بْنِ بَهْدَلَةَ، عَنْ أَبِي وَائِلٍ، عَنِ ابْنِ مَسْعُودٍ قَالَ: لَمَّا قَسَّمَ رَسُولُ اللهِ صلى الله عليه وسلم غَنَائِمَ حُنَيْنٍ بِالْجِعْرَانَةِ ازْدَحَمُوا عَلَيْهِ، فَقَالَ رَسُولُ اللهِ صلى الله عليه وسلم: إِنَّ عَبْدًا مِنْ عِبَادِ اللهِ بَعَثَهُ اللَّهُ إِلَى قَوْمٍ، فَكَذَّبُوهُ وَشَجُّوهُ، فَكَانَ يَمْسَحُ الدَّمَ عَنْ جَبْهَتِهِ وَيَقُولُ: اللَّهُمَّ اغْفِرْ لِقَوْمِي، فَإِنَّهُمْ لاَ يَعْلَمُونَ. قَالَ عَبْدُ اللهِ بْنُ مَسْعُودٍ: فَكَأَنِّي أَنْظُرُ إِلَى رَسُولِ اللهِ صلى الله عليه وسلم يَحْكِي الرَّجُلَ يَمْسَحُ عَنْ جَبْهَتِهِ.
sunnah.com