Abu Hurayrah (may Allah be pleased with him) narrated that the Prophet (peace and blessings be upon him) said: "Every prophet has a supplication that is certainly answered. I have saved my supplication for the Day of Resurrection, with which I will intercede, and it will reach every member of my Ummah except the one who associates partners with Allah."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب النفقات / 15837