Narrated Mus’ab bin Sa’d : Once Sa’d (bin Abi Waqqas) thought that he was superior to those who were below him. On that the Prophet (ﷺ) said, “You gain no victory nor sustenance except through (the supplication) of your weak ones.”
حَدَّثَنَا سُلَيْمَانُ بْنُ حَرْبٍ، حَدَّثَنَا مُحَمَّدُ بْنُ طَلْحَةَ، عَنْ طَلْحَةَ، عَنْ مُصْعَبِ بْنِ سَعْدٍ، قَالَ رَأَى سَعْدٌ ـ رضى الله عنه ـ أَنَّ لَهُ فَضْلاً عَلَى مَنْ دُونَهُ، فَقَالَ النَّبِيُّ صلى الله عليه وسلم “ هَلْ تُنْصَرُونَ وَتُرْزَقُونَ إِلاَّ بِضُعَفَائِكُمْ ”.
Reference : Sahih al-Bukhari 2896
In-book reference : Book 56, Hadith 110
USC-MSA web (English) reference : Vol. 4, Book 52, Hadith 145