The Book Pertaining to the Remembrance of Allah, Supplication, Repentance and Seeking Forgiveness (Kitab Al-Dhikr)
Muslim :: Book 35 : Hadith 6562
Abu Huraira reported that when Allah's Messenger (may peace be upon him) set out on a journey in the morning, he used to say:" A listener listened to our praising Allah (for) His goodly trial of us. Our Lord! acompany us, guard us and bestow upon us Thy grace. I am seeker of refuge in Allah from the Fire."