Hadith
حَدَّثَنَا قُتَيْبَةُ بْنُ سَعِيدٍ، حَدَّثَنَا حَاتِمٌ، عَنْ يَزِيدَ بْنِ أَبِي عُبَيْدٍ، قَالَ قُلْتُ لِسَلَمَةَ بْنِ الأَكْوَعِ عَلَى أَىِّ شَىْءٍ بَايَعْتُمْ رَسُولَ اللَّهِ صلى الله عليه وسلم يَوْمَ الْحُدَيْبِيَةِ. قَالَ عَلَى الْمَوْتِ.
Narrated Yazid bin Abi Ubaid:I said to Salama bin Al-Akwa`, "For what did you give the Pledge of allegiance to Allah's Messenger (ﷺ) on the day of Al-Hudaibiya?" He replied, "For death (in the Cause of Islam)
Sahih
Sahih al-Bukhari 4169 ·Book 64, Hadith 211·Also available on sunnah.com·