Sahih Muslim 1742
Sahih Muslim · Book 32: The Book of Jihad and Expeditions · It is recommended to pray for victory when meeting the enemy
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.