Answer
Wa `alaykum As-Salamu wa Rahmatullahi wa Barakatuh.
In the Name of Allah, Most Gracious, Most Merciful.
All praise and thanks are due to Allah, and peace and blessings be upon His Messenger.
In this fatwa:
It is not Sunnah for pilgrims to fast on the Day of Arafah so that they will be strong enough to devote themselves to worship and supplicating. However, it is Sunnah for non-pilgrims to fast on that day.
In this regard, Sheikh Sayyed Sabiq states in his well-known book Fiqh As-Sunnah:
It is confirmed that the Prophet (peace be upon him) did not fast on the Day of Arafah. The Prophet said: “Verily the Day of Arafah, the Day of Sacrifice (Yawm An-Nahr), and the days of Tashriq (the 10th, 11th and 12th of Dhul Hijjah) are our days of festivities. These are the days of eating and drinking.” (Abu Dawud)
It is also established that the Prophet forbade fasting on the Day of Arafah for those who are at Arafah (for pilgrimage).
Abu Hurairah narrated that the Prophet; “Forbade fasting on the day of Arafah for one who is actually at Arafah.”(Ahmad, Abu Dawud, An-Nasa’i, and Ibn Majah)
This has led most scholars to conclude that it is not desirable to fast on the Day of Arafah, so that the pilgrim will be strong enough to devote himself wholeheartedly to worship and supplicating.
Some of the hadiths that encourage fasting on the Day of Arafah are concerned with the people who are not staying at Arafah as pilgrims performing Hajj.
Almighty Allah knows best.
Editor’s note: This fatwa is from Ask the Scholar’s archive and was originally published at an earlier date.