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كتاب الدعوات
80  
Invocations
(1)
Chapter: For every Prophet there is one invocation surely granted
(1)
باب وَلِكُلِّ نَبِيٍّ دَعْوَةٌ مُسْتَجَابَةٌ
Sahih al-Bukhari 6305

Narrated Anas:

that the Prophet (ﷺ) said, "For every prophet there is an invocation that surely will be responded by Allah," (or said), "For every prophet there was an invocation with which he appealed to Allah, and his invocation was accepted (in his lifetime), but I kept my (this special) invocation to intercede for my followers on the Day of Resurrection."

وَقَالَ لِي خَلِيفَةُ قَالَ مُعْتَمِرٌ سَمِعْتُ أَبِي، عَنْ أَنَسٍ، عَنِ النَّبِيِّ صلى الله عليه وسلم قَالَ ‏ "‏ كُلُّ نَبِيٍّ سَأَلَ سُؤْلاً ـ أَوْ قَالَ لِكُلِّ نَبِيٍّ دَعْوَةٌ قَدْ دَعَا بِهَا ـ فَاسْتُجِيبَ، فَجَعَلْتُ دَعْوَتِي شَفَاعَةً لأُمَّتِي يَوْمَ الْقِيَامَةِ ‏"‏‏.‏
Reference : Sahih al-Bukhari 6305
In-book reference : Book 80, Hadith 2
USC-MSA web (English) reference : Vol. 8, Book 75, Hadith 317
  (deprecated numbering scheme)