The Ten Days of Zil Hijjah

بِسْــــــــــــــــــمِ اﷲِالرَّحْمَنِ اارَّحِيم

Abdullah ibn Abbas (R.A) related that Rasoolullah (S.A.W) said : "There are
no other days during which pious actions are so pleasing to Allah Ta'ala as
the first ten days of Zil Hijjah" , the sahabas submitted :" Oh Rasoolullah,
not even jihad in the path of Allah Ta'ala ?" Rasoolullah (S.A.W) answered
"Yes not even jihad excepts in the case of a person who goes for jihad along
with his life and his property and does not comeback."
(Bukhari)

Abu Hurairah (R.A) reported that Rasoolullah (S.A.W) said : No other days
of the world are loved by Allah Ta'ala that He is worshiped in than the ten
days of Zil Hijjah (because) one day's fast during it is equal to one year's
fast and one night is equal to Lailathul Qadr.
(Ibn Majah)   

The Day of Arafah

Abu Qatadah (R.A) relates that Rasoolullah (S.A.W) was asked about
observing the fast on the day of Arafah. He (S.A.W) replied : It makes 
amends for the sins (committed) during past year and the subsequent 
year.
 (Muslim)

Ayesha (R.A) related that Rasoolullah (S.A.W) said : "There is no other
day on which Allah Ta'ala frees the largest number of his slaves from the 
fire of Jahannam than the day of Arafah.
(Muslim)
    
Ummu Fardhl (R.A) relates that few people were disputing regarding
the fast of Rasoolullah (S.A.W) on the day of Arafah. Few of them
said he is fasting and few of them said he is not fasting thus she sent
a pot of milk to him while he was on his camel in the plains of Arafah
thus he drank it. 
(Muslim) 

Note : It is recommended to fast on the Day of Arafah (9 Zil Hijjah),
unless one is a pilgrim present at Arafah, when it is better not to fast.
It is not offensive for such a person to fast, though it is better for
him not to.     


Amr ibn Shuaib (R.A) reported from his father then grandfather that
Rasolullah (S.A.W) said :" The best of the Duas is the Dua on the Day
of Arafah, the best of what I have said and the prophets before me is :    


Laa-'i-laa-ha 'il-lal-laa-hu
There is none worthy of worship besides Allah,


wah-da-hoo
He is one

laa sha-reeka la-hoo
He has no partner.

la-hul mul-ku
His is the Kingdom


wa-la-hul ham-du
and for Him is all praise.

wa-hu-wa 'a-laa kul-li shay-'in qadeer
And He has power over everything.