Sayyiduna Abu Huraira (may Allah be pleased with him) narrated from the Messenger of Allah (peace and blessings be upon him), he (peace be upon him) said: "Your fast is on the day when you (see the moon and) begin fasting, and your Eid al-Fitr is on the day when you (complete Ramadan and) stop fasting."
Hadith Referenceمسند اسحاق بن راهويه / كتاب الصوم / 416
Hadith Takhrij«سنن ابوداود ، كتاب الصيام ، باب اذا اخطا القوم الهلال ، رقم : 2324 . سنن ترمذي ، ابواب الصوم ، باب الصوم يوم تصومون والفطر الخ ، رقم : 697 . سنن ابن ماجه ، رقم : 1660 . قال الشيخ الالباني : صحيح .»
Explanation & Benefits
Hafiz Abdush Shakoor Tirmidhi
Benefits: From the mentioned hadith, it is understood that fasting and breaking the fast to celebrate Eid should be done together with other Muslims; it is not permissible for anyone to fast alone or to begin celebrating Eid alone. This is because fasting in the blessed month of Ramadan and celebrating Eid are acts of collective worship.