Hadith
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 "
Narrated Abu Huraira: Allah's Messenger (ﷺ) 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."
Sahih al-Bukhari 6304 In-book : Book 80, Hadith 1 USC-MSA web (English) : Vol. 8, Book 75, Hadith 317 (deprecated)
Special invocation for intercession by prophet, a very special dua, a precious dua, dua for ummah