Abdullah bin Yazid (may Allah be pleased with him) said that he (peace and blessings be upon him) said: "There is no deceased person over whom a group of Muslims pray the funeral prayer, their number reaching a hundred, all of them interceding for him, except that their intercession for him is accepted."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الجنائز / 6903