Sayyiduna Samurah (may Allah be pleased with him) says: The Messenger of Allah (peace and blessings be upon him) forbade us from wisal (fasting continuously without breaking the fast) in the month of fasting, and he disliked it, but this prohibition was not a binding command.
Hadith Referenceالمعجم الكبير للطبراني / باب السين / 6981