Sayyiduna Imran bin Husayn (may Allah be pleased with him) narrates: It was said in the presence of the Prophet (peace and blessings of Allah be upon him) that a certain person never breaks his fast during the day, only at night (i.e., he keeps a voluntary fast every day), so the Prophet (peace and blessings of Allah be upon him) said: "He has neither fasted nor left fasting." (Imam Ibn Hibban, may Allah have mercy on him, says:): In this narration, there is evidence that the words which are mentioned in the narration attributed to Sayyiduna Abdullah bin Amr (may Allah be pleased with him): "Whoever always fasts, in reality, he has neither fasted nor left fasting." This refers to always doing so, and it includes those days on which fasting is prohibited, such as the days of Tashreeq and the days of Eid.
Hadith Referenceصحیح ابن حبان / كتاب الصوم / 3582
Hadith Gradingفضيلة الشيخ الإمام محمد ناصر الدين الألبانيصحيح - «التعليق» -أيضا-.فضيلة الشيخ العلّامة شُعيب الأرناؤوطإسناده صحيح على شرط مسلم