The Book of Jihad and Expeditions
32/7. Chapter:
It is recommended to pray for victory when meeting the enemy
Sahih Muslim
وَحَدَّثَنَاهُ إِسْحَاقُ بْنُ إِبْرَاهِيمَ، وَابْنُ أَبِي عُمَرَ، جَمِيعًا عَنِ ابْنِ عُيَيْنَةَ، عَنْ إِسْمَاعِيلَ، بِهَذَا الإِسْنَادِ وَزَادَ ابْنُ أَبِي عُمَرَ فِي رِوَايَتِهِ " مُجْرِيَ السَّحَابِ " .
This hadith has been narrated on the authority of Ibn 'Uyaina through another chain of transmitters (who added the words)" the Disperser of clouds" in his narration.
Reference : Sahih Muslim 1742dIn-book reference : Book 32, Hadith 26USC-MSA web (English) reference : Book 19, Hadith 4317