We went out intending (to visit) the Messenger of Allah ﷺ and Wa'il ibn Hujr was with us. His enemy caught him. The people desisted from swearing an oath, but I took an oath that he was my brother. So he left him. We then came to the Messenger of Allah ﷺ, and I informed him that the people desisted from taking the oath, but I swore that he was my brother. He said: You spoke the truth: A Muslim is a brother of a Muslim. (Using translation from Abū Dāʾūd 3256)
خَرَجْنَا نُرِيدُ رَسُولَ اللهِ ﷺ وَمَعَنَا وَائِلُ بْنُ حُجْرٍ فَأَخَذَهُ عَدُوٌّ لَهُ فَتَحَرَّجَ الْقَوْمُ أَنْ يَحْلِفُوا وَحَلَفْتُ أَنَا أَنَّهُ أَخِي فَخُلِّيَ سَبِيلُهُ فَأَتَيْتُ رَسُولَ اللهِ ﷺ فَقُلْتُ إِنَّ الْقَوْمَ تَحَرَّجُوا أَنْ يَحْلِفُوا وَحَلَفْتُ أَنَّهُ أَخِي فَقَالَ «صَدَقْتَ الْمُسْلِمُ أَخُو الْمُسْلِمِ»