9th day of Zilhajjah is called The Day of Arafah while the night between Zilhajjah 8 and 9 is called Night of Arafah. There have been reported different acts to be performed on these occasions.
The day of Arafah is one of the most sacred days of the Islamic Calendar. On this day Allah invites its servants towards his worship and obedience, and spreads his bounties and blessings. Imam Zaynul Abidin (as) says about this great day: “O God, this is the day of Arafah a day which you have made noble, given honor and magnified within it. You have spread your mercy, showed kindness through your pardon, made plentiful your giving and by it you have been gracious towards your servants.” Sahifa as-Sajjadiyyah, Du’a no 47).
Holy Prophet Muhammad (PBUH ) said: “your Adiyah (prayers) are fulfilled and repentance is accepted in this night.” He who spends this night in worship will be given the reward of 170 years of worship.