To give a Bai'a for not to flee during a battle
حَدَّثَنَا حَفْصُ بْنُ عُمَرَ، حَدَّثَنَا شُعْبَةُ، عَنْ حُمَيْدٍ، قَالَ سَمِعْتُ أَنَسًا ـ رضى الله عنه ـ يَقُولُ كَانَتِ الأَنْصَارُ يَوْمَ الْخَنْدَقِ تَقُولُ نَحْنُ الَّذِينَ بَايَعُوا مُحَمَّدَا عَلَى الْجِهَادِ مَا حَيِينَا أَبَدَا فَأَجَابَهُمُ النَّبِيُّ صلى الله عليه وسلم فَقَالَ اللَّهُمَّ لاَ عَيْشَ إِلاَّ عَيْشُ الآخِرَهْ فَأَكْرِمِ الأَنْصَارَ وَالْمُهَاجِرَهْ
Narrated Anas: On the day (of the battle) of the Trench, the Ansar were saying, "We are those who have sworn allegiance to Muhammad for Jihaid (for ever) as long as we live." The Prophet (ﷺ) replied to them, "O Allah! There is no life except the life of the Hereafter. So honor the Ansar and emigrants with Your Generosity."