Narrated Ibn 'Abbas:
"A man said 'O Messenger of Allah! Which deed is most virtuous to Allah?' He said: 'Al-Hallul-Murtahil'' He said: 'What is Al-Hallul-Murtahil?' He said: 'The one who recites from the beginning of the Qur'an to the end of it, every time he sets out (on a trip).'" (PT)
English reference (PT): Vol. 5, Book 43, Hadith 2948 (PT)
Arabic reference (PT): Book 46, Hadith 3200 (PT)