Sahih al-Bukhari, Book 56, Hadith 110 (In-Book) ⓘ
Narrated Mus`ab bin Sa`d: Once Sa`d (bin Abi Waqqas) thought that he was superior to those who were below him in rank. On that the Prophet said, "You gain no victory or livelihood except through (the blessings and invocations of) the poor amongst you."
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 " .
also referenced under: Hadith 2896 (DarusSalam) & Volume 4, Book 52, Hadith 145 (USC-MSA)