Hadith 4:136
‘A’isha reported the Prophet as saying, "If a company of Muslims to the number of a hundred pray over a dead person, all of them interceding for him, their intercession for him will be accepted.” Muslim transmitted it.
وَعَنْ عَائِشَةَ رَضِيَ اللَّهُ عَنْهَا عَنِ النَّبِيِّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ قَالَ: " مَا مِنْ مَيِّتٍ تُصَلِّي عَلَيْهِ أُمَّةٌ مِنَ الْمُسْلِمِينَ يَبْلُغُونَ مِائَةً كُلُّهُمْ يَشْفَعُونَ لَهُ: إِلَّا شفعوا فِيهِ " رَوَاهُ مُسلم
Original Reference: Mishkat al-Masabih 1661