Musnad Abu Ya'la al-Mawsili 148:33

Abu Hammam narrated to us, Muhammad ibn Shu'ayb ibn Shapur narrated to us, Sa'id ibn Khalid ibn Abi Tawil al-Qurashi narrated to us, he said: I heard Anas ibn Malik narrating from the Messenger of Allah (may Allah bless him and grant him peace) that he said: "Whoever guards for one night on the seashore, it is better than the worship of a man among his family for a thousand years; the year is three hundred and sixty days, each day is a thousand years."