(the freed slave of 'Umar bin 'Ubaidullah) I was Umar's clerk. Once Abdullah bin Abi Aufa wrote a letter to 'Umar when he proceeded to Al-Haruriya. I read in it that Messenger of Allah ﷺ in one of his military expeditions against the enemy, waited till the sun declined and then he got up amongst the people saying, "O people! Do not wish to meet the enemy, and ask Allah for safety, but when you face the enemy, be patient, and remember that Paradise is under the shades of swords." Then he said, "O Allah, the Revealer of the Holy Book, and the Mover of the clouds and the Defeater of the clans, defeat them, and grant us victory over them." (Using translation from Bukhārī 3024)
كَتَبَ إِلَيْهِ عَبْدُ اللهِ بْنُ أَبِي أَوْفَى ؓ حِينَ خَرَجَ إِلَى الْحَرُورِيَّةِ فَقَرَأْتُهُ فَإِذَا فِيهِ إِنَّ رَسُولَ اللهِ ﷺ فِي بَعْضِ أَيَّامِهِ الَّتِي لَقِيَ فِيهَا الْعَدُوَّ انْتَظَرَ حَتَّى مَالَتِ الشَّمْسُ ثُمَّ قَامَ فِي النَّاسِ فَقَالَ يَا أَيُّهَا النَّاسُ لَا تَتَمَنَّوْا لِقَاءَ الْعَدُوِّ وَاسْأَلُوا اللهَ الْعَافِيَةَ فَإِذَا لَقِيتُمُوهُمْ فَاصْبِرُوا وَاعْلَمُوا أَنَّ الْجَنَّةَ تَحْتَ ظِلَالِ السُّيُوفِ ثُمَّ قَالَ اللهُمَّ مُنْزِلَ الْكِتَابِ وَمُجْرِيَ السَّحَابِ وَهَازِمَ الْأَحْزَابِ اهْزِمْهُمْ وَانْصُرْنَا عَلَيْهِمْ قَالَ وَقَالَ أَبُو النَّضْرِ وَبَلَغَنَا أَنَّ النَّبِيَّ ﷺ دَعَا فِي مِثْلِ ذَلِكَ فَقَالَ أَنْتَ رَبُّنَا وَرَبُّهُمْ وَنَحْنُ عَبِيدُكَ وَهُمْ عَبِيدُكَ وَنَوَاصِينَا وَنَوَاصِيهِمْ بِيَدِكَ فَاهْزِمْهُمْ وَانْصُرْنَا عَلَيْهِمْ