Sahih Bukhari Volume 4, Book 56, Hadith 2967

ثُمَّ قَامَ فِي النَّاسِ قَالَ ‏"‏ أَيُّهَا النَّاسُ، لاَ تَتَمَنَّوْا لِقَاءَ الْعَدُوِّ، وَسَلُوا اللَّهَ الْعَافِيَةَ، فَإِذَا لَقِيتُمُوهُمْ فَاصْبِرُوا، وَاعْلَمُوا أَنَّ الْجَنَّةَ تَحْتَ ظِلاَلِ السُّيُوفِ، ثُمَّ قَالَ اللَّهُمَّ مُنْزِلَ الْكِتَابِ وَمُجْرِيَ السَّحَابِ وَهَازِمَ الأَحْزَابِ، اهْزِمْهُمْ وَانْصُرْنَا عَلَيْهِمْ ‏"‏‏.

and then he got up among the people and said, "O people! Do not wish to face the enemy (in a battle) and ask Allah to save you (from calamities) but if you should face the enemy, then be patient and let it be known to you that Paradise is under the shades of swords." He then said,, "O Allah! The Revealer of the (Holy) Book, the Mover of the clouds, and Defeater of Al-Ahzab (i.e. the clans of infidels), defeat them infidels and bestow victory upon us."