Sahih Muslim
The Book of Faith (Kitab Al-Iman)
Book Number: 001 / Hadith Number: 385
Abu Huraira reported: Verity the Messenger of Allah (may peace be upon him) said: There is for every apostle a (special) prayer with which he would pray. I wish I could reserve, my prayer for intercession of my Ummah on the Day of Resurrection.