عن هنيدة ابن خالد عن امرأته عن بعض أزواج النبي صلى الله عليه وسلم قالت “كان رسول الله صلى الله عليه وسلم يصوم تسع ذي الحجة ، ويوم عاشوراء ، وثلاثة أيام من كل شهر : أول اثنين من الشهر وخميسين “صحيح أبو داود وصحيح النسائى
Hunaydah ibn Khaalid narrated upon the authority of his wife who said: “Some of the wives of the Prophet sallAllaahu 3Alayhi wa sallam told me that the Prophet sallAllaahu 3Alayhi wa sallam used to fast the Day of 3Aashoorah, the first nine days of Dhul-Hijjah, and three days out of every month*….” (1)
(*13th, 14th, and 15th of every month)
Imaam An-Nawwawee said with reference to fasting the first nine days of Dhul-Hijjah: “It is extremely preferable to do so”.
Shaykh 3Uthaymeen (may Allaah have mercy upon him) was asked about fasting the first [nine] days of Dhul-Hijjah?
He replied: “Fasting the first [nine] of Dhul-Hijjah is from the righteous actions without doubt. And the Prophet sallAllaahu 3Alayhi wa sallam said,“There are not any days in which righteous actions are done that are more beloved to Allaah than these ten days.” They said, “Oh Messenger of Allaah, not even jihaad in Allaah’s cause?”
He said: “Not even jihaad in Allaah’s cause,Except for a man who left out with his self and his wealth, and he did not return with either.”
So fasting is included in the general context of this hadeeth. And there appears a hadeeth stating that the Messenger of Allaah sallAllaahu 3Alayhi wa sallam used to fast the first ten of Dhul-Hijjah, not counting the 3Eed [in other words, the first nine days of Dhul-Hijjah].
And Imaam Ahmad ibn Hanbal rahimahullaah takes this position and it is authentic.Fasting in the first ten [of Dhul-Hijjah, excluding the 3Eed] is sunnah. Yes.”
Shaykh Salih Al-Munajjid says: “It is Sunnah for the Muslim to fast on the first nine days of Dhul-Hijjah, because the Prophet sallAllaahu 3Alayhi wa sallam encouraged us to do righteous deeds in the first ten days of Dhu’l-Hijjah, and fasting is one of the best of deeds, which Allaah has chosen for Himself as it says in the hadeeth qudsee: “Allaah says: ‘All the deeds of the son of Adam are for him, except fasting, which is for Me and I shall reward for it.” ( 2) (3)
Making up Missed Ramadaan Fasts & 10 Days of Dhul-Hijjah:
Shaykh Muhammad ibn Saalih al-3Uthaymeen (may Allaah have mercy on him) was asked about combining making up a missed obligation and doing something that is mustahabb (such as fasting the day 3Aashoora’ which coincides with making up a missed Ramadaan fast)?
He replied: “With regard to obligatory and voluntary fasts, what is prescribed in sharee3ah and what makes sense is to start with the obligatory fasts and then do the naafil ones, because the obligatory fast is a debt which must be paid. But if a person observes a voluntary fast before making up what he owes then the correct view is that his voluntary fast is valid so long as there is still enough time to make up the missed fasts, because a person may make up missed Ramadaan fasts so long as there is still enough time for him to do so before the next Ramadaan comes.
But if he has the intention of fasting this day to make up for a missed Ramadaan fast, he will have two rewards – one for the day of 3Arafah or 3Ashoora’ and another for making up the missed fast. (4)
(1) Ahmad, An-Nasaa’ee
(2) Narrated by al-Bukhaari, 1805.
(4) Majmoo’ Fataawa Ibn 3Uthaymeen, 20/438