Suwayd ibn Hanzalah reported: We went out intending to meet the Messenger of Allah, peace and blessings be upon him, and with us was Wa’il ibn Hujr. Then, one of his enemies seized him, and the people resisted swearing an oath, but I swore an oath, saying, “He is my brother!” They let him go on his way, and we came to the Messenger of Allah. I told him that the people resisted swearing an oath, but I swore an oath that he was my brother. The Prophet said, “You spoke the truth. The Muslim is the brother of another Muslim.”
Source: Sunan Abī Dāwūd 3256
Grade: Sahih (authentic) according to Al-Albani
عَنْ سُوَيْدِ بْنِ حَنْظَلَةَ قَالَ خَرَجْنَا نُرِيدُ رَسُولَ اللَّهِ صَلَّى اللهُ عَلَيْهِ وَسَلَّمَ وَمَعَنَا وَائِلُ بْنُ حُجْرٍ فَأَخَذَهُ عَدُوٌّ لَهُ فَتَحَرَّجَ الْقَوْمُ أَنْ يَحْلِفُوا وَحَلَفْتُ أَنَّهُ أَخِي فَخَلَّى سَبِيلَهُ فَأَتَيْنَا رَسُولَ اللَّهِ صَلَّى اللهُ عَلَيْهِ وَسَلَّمَ فَأَخْبَرْتُهُ أَنَّ الْقَوْمَ تَحَرَّجُوا أَنْ يَحْلِفُوا وَحَلَفْتُ أَنَّهُ أَخِي قَالَ صَدَقْتَ الْمُسْلِمُ أَخُو الْمُسْلِمِ
3256 سنن أبي داود كتاب الأيمان والنذور باب المعاريض في اليمين
6704 المحدث الألباني خلاصة حكم المحدث صحيح في صحيح الجامع