Sahih Bukhari
Prophets
Volume: 004 / Book Number: 055 / Hadith Number: 588
Narrated Abu Humaid As-Sa'idi:
The people asked, "O Allah's Apostle! How shall we (ask Allah to) send blessings on you?" Allah's Apostle replied, "Say: O Allah! Send Your Mercy on Muhammad and on his wives and on his off spring, as You sent Your Mercy on Abraham's family; and send Your Blessings on Muhammad and on his offspring, as You sent Your Blessings on Abraham's family, for You are the Most Praise-worthy, the Most Glorious."