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.
Dear questioner, we would like to thank you for your interesting question.
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, we will cite what Sheikh Sayyed Sabiq, states in his well-known book, Fiqh As-Sunnah:
It is confirmed that the Prophet (peace and blessings be upon him) did not fast on the Day of `Arafah. The Prophet (peace and blessings be upon him) said: "Verily the Day of `Arafah, the Day of Sacrifice (Yawm An-Nahr), and the days of Tashreeq (the 10th, 11th and 12th of Dhul-Hijjah) are our days of festivities. These are the days of eating and drinking." It is also established that the Prophet (peace and blessings be upon him) forbade fasting on the Day of `Arafah for those who are at `Arafah (for pilgrimage).
Abu Hurairah, (may Allah be pleased with him), narrates that the Prophet, (peace and blessings be upon him), “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 desirable not 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.
