Yahya related to me from Malik from Nafi from Abdullah ibn Umarthat the Messenger of Allah, may Allah bless him and grant him peace,forbade fasting for two days or more without breaking the fast inbetween. They said, "But Messenger of Allah, you practise wisal." Hereplied, "I am not the same as you. I am fed and given to drink."
USC-MSA web (English) reference: Book 18, Hadith 38
Arabic reference: Book 18, Hadith 672