Sahih Muslim Book - 32, Hadith - 4542

وَحَدَّثَنِى مُحَمَّدُ بْنُ رَافِعٍ حَدَّثَنَا عَبْدُ الرَّزَّاقِ أَخْبَرَنَا ابْنُ جُرَيْجٍ أَخْبَرَنِى مُوسَى بْنُ عُقْبَةَ عَنْ أَبِى النَّضْرِ عَنْ كِتَابِ رَجُلٍ مِنْ أَسْلَمَ مِنْ أَصْحَابِ النَّبِىِّ -صلى الله عليه وسلم- يُقَالُ لَهُ عَبْدُ اللَّهِ بْنُ أَبِى أَوْفَى فَكَتَبَ إِلَى عُمَرَ بْنِ عُبَيْدِ اللَّهِ حِينَ سَارَ إِلَى الْحَرُورِيَّةِ يُخْبِرُهُ أَنَّ رَسُولَ اللَّهِ -صلى الله عليه وسلم- كَانَ فِى بَعْضِ أَيَّامِهِ الَّتِى لَقِىَ فِيهَا الْعَدُوَّ يَنْتَظِرُ حَتَّى إِذَا مَالَتِ الشَّمْسُ قَامَ فِيهِمْ فَقَالَ « يَا أَيُّهَا النَّاسُ لاَ تَتَمَنَّوْا لِقَاءَ الْعَدُوِّ وَاسْأَلُوا اللَّهَ الْعَافِيَةَ فَإِذَا لَقِيتُمُوهُمْ فَاصْبِرُوا وَاعْلَمُوا أَنَّ الْجَنَّةَ تَحْتَ ظِلاَلِ السُّيُوفِ ». ثُمَّ قَامَ النَّبِىُّ -صلى الله عليه وسلم- وَقَالَ « اللَّهُمَّ مُنْزِلَ الْكِتَابِ وَمُجْرِىَ السَّحَابِ وَهَازِمَ الأَحْزَابِ اهْزِمْهُمْ وَانْصُرْنَا عَلَيْهِمْ ».

It was narrated from Abu Nadr, from the letter of a man of Aslam who was one of the Companions of the Prophet (s.a.w) who was called 'Abdullah bin Abi Awfa, who wrote to 'Umar bin 'Ubaidullah, when he went to fight the Haruriyyah; he told him that on one of the days when the Messenger of Allah (s.a.w) met the enemy, he waited until the sun went down, then he stood up and said: "O people, do not wish to meet the enemy, and ask Allah to keep you safe and sound. When you do meet them, then be steadfast, and realize that Paradise lies in the shade of the swords." Then the Prophet (s.a.w) stood up and said: "O Allah, Revealer of the Book, Sender of the clouds and Defeater of the confederates, defeat them, and grant us victory over them."