It was reported from Abu Qataadah (may Allaah be pleased with him) that the Messenger of Allaah sallAllaahu 3Alayhi wa sallam was asked about fasting on the Day of 3Arafah. He said, “It expiates for the sins of the previous year and of the coming year.” (1)
In another narration: “I ask Allaah that it may expiate for (the sins of) the year that comes before it and the year that comes after it.”
Fasting The Day of 3Arafah for Different Moon Sighting Countries
The day of 3Arafah and the fast thereon is the ninth day of the month of Dhul-Hijjah, which is defined for each country according to their sighting of the new moon of Dhul-Hijjah. So it may be on Thursday for the people of Makkah, and for others it may be on Wednesday or Saturday. It is not essential to follow the people of Makkah when there are differences in the sighting of the new moon. This is the most correct of the scholarly views, that each country has its own sighting when there is a difference concerning that. (1)
Shaykh Ibn 3Uthaymeen (may Allaah have mercy on him) was asked: what if the day of 3Arafah is different because of the moon being sighted at different times in different countries? Should we fast according to the moon sighting in the country where we are or according to the moon sighting in al-Haramayn (the two Holy Sanctuaries)?
He replied: ”This is based on a difference of opinion among the scholars: Is there only one moon sighting for the whole world or does it vary according to when the moon rises in different places?
The correct view is that it varies according to when the moon rises in different places.
For example, if the moon is sighted in Makkah, and today is the ninth, and it is sighted elsewhere one day before Makkah, and the day of 3Arafah in Makkah is the tenth for them, it is not permissible for them to fast on this day because it is 3Eid.
Similarly if it so happens that they sight the moon after Makkah, and the 9th in Makkah is the 8th for them, then they should fast the day that is the 9th for them, which is the 10th in Makkah. This is the correct view, because the Prophet sallAllaahu 3alayhi wa sallam said:“When you see it (the new moon) fast and when you see it break your fast.”
Those who did not see the moon in their own location have not seen it. Just as people are unanimously agreed that the times for dawn and sunset vary according to their own location, so too the months are also worked out by location, just like the daily timings.(2)
=====================================================References: (1) http://islamqa.com/en/ref/140011 (2) Majmoo3 al-Fataawa, 20. http://islamqa.com/en/ref/40720/