Sahih al-Bukhari, Hadith 6304 ⓘ
Narrated Abu Huraira: Allah's Messenger said, "For every prophet there is one (special invocation (that will not be rejected) with which he appeals (to Allah), and I want to keep such an invocation for interceding for my followers in the Hereafter."
حَدَّثَنَا إِسْمَاعِيلُ، قَالَ حَدَّثَنِي مَالِكٌ، عَنْ أَبِي الزِّنَادِ، عَنِ الأَعْرَجِ، عَنْ أَبِي هُرَيْرَةَ، أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم قَالَ " لِكُلِّ نَبِيٍّ دَعْوَةٌ يَدْعُو بِهَا، وَأُرِيدُ أَنْ أَخْتَبِئَ دَعْوَتِي شَفَاعَةً لأُمَّتِي فِي الآخِرَةِ " .
also referenced under: Book 80, Hadith 1 (In-Book) & Volume 8, Book 75, Hadith 317 (USC-MSA)