Is it Sunnah to do ghusl on the Day of ‘Arafah?
Question

Is it Sunnah to do ghusl on the Day of ‘Arafah?
Praise be to Allah.Firstly: It is not stipulated that one should be in a state of purity for the standing in ‘Arafah. The scholars are agreed that it is valid for a woman who is menstruating or a person who is in a state of janaabah to stand in ‘Arafah. However it is mustahabb (recommended) for the one who stands in ‘Arafah to be free of impurity, both major and minor, because he is going to be mentioning the name of Allah, may He be exalted, and it is mustahabb to do wudoo’ before mentioning the name of Allah, may He be exalted.
See also the answer to question no. 82029 .
Secondly: It is proven from more than one of the Sahaabah that they did ghusl for the day of ‘Arafah – such as Ibn Mas‘ood, Ibn ‘Umar and ‘Ali (may Allah be pleased with them).
Al-Bayhaqi (6124) narrated that Zaadhaan said: A man asked ‘Ali (may Allah be pleased with him) about bathing. He said: Bathe every day if you wish. He said: No, (I mean) ghusl (in the sense of purification). He said: On Fridays, the day of ‘Arafah, the Day of Sacrifice (Eid al-Adha) and the day of (Eid) al-Fitr.
Classed as saheeh by al-Albaani in al-Irwa’ (1/177).
It says in al-Mawsoo‘ah al-Fiqhiyyah (45/323)
The Shaafa‘is, Hanbalis and Maalikis – according to one opinion – are of the  view that it is Sunnah to do ghusl for the standing in ‘Arafah, because of the report narrated from ‘Ali, Ibn Mas‘ood and Ibn ‘Umar (may Allah be pleased with them), that they used to do ghusl when they went to ‘Arafah.
Moreover, it is an act of worship for which people gather in one place, so it is prescribed to do ghusl for it, as in the case of Jumu‘ah and Eid prayers.
The Hanafis and the Maalikis, according to the official opinion, are of the view that doing ghusl for the day of ‘Arafah is mustahabb. End quote.
According to the fuqaha’, mustahabb refers to an unconfirmed Sunnah (Sunnah ghayr mu’akkadah), i.e., something that the Messenger (blessings and peace of Allah be upon him) did not do as a consistent practice.
See: Haashiyat Ibn ‘Aabideen (2/411)
Thus it becomes clear that the four madhhabs are agreed that it is prescribed to do ghusl on the day of ‘Arafah, and that the one who does it will be rewarded. The evidence for it being prescribed is the action of the Sahaabah (may Allah be pleased with them).
Ibn Maajah (1316) narrated from al-Faakih ibn Sa‘d that the Messenger of Allah (blessings and peace of Allah be upon him) used to do ghusl on the day of (Eid) al-Fitr, the Day of Sacrifice (Eid al-Adha) and the day of ‘Arafah.
But this is a mawdoo‘ (fabricated) hadith, as stated by al-Albaani in Da‘eef Ibn Maajah.
It was also narrated that the Prophet (blessings and peace of Allah be upon him) said: “Ghusl on these days is obligatory: Friday, the day of (Eid) al-Fitr, the Day of Sacrifice (Eid al-Adha) and the day of ‘Arafah.” But this was classed as da‘eef by al-Albaani in Da‘eef al-Jaami‘ (3929)
In fatwa no. 81949 we stated that it is mustahabb for the one who wants to gather with the people to do ghusl, clean himself and put on perfume. That includes ghusl for the standing in ‘Arafah.
Thirdly: It should be understood that doing ghusl for the day of ‘Arafah is not for every Muslim; rather it is only for the pilgrim, because this is what is narrated from the Sahaabah (may Allah be pleased with them), and because it is bathing for the purpose of gathering with people, and the gathering only takes place in ‘Arafah.
Shaykh al-Islam Ibn Taymiyah (may Allah have mercy on him) said:
There is no report from the Prophet (blessings and peace of Allah be upon him) or from his companions of any ghusl in Hajj except three: ghusl when entering ihram, ghusl when entering Makkah, and ghusl on the day of ‘Arafah. End quote. Mamoo‘ al-Fataawa (26/132)
Fourthly: The words Sunnah and mustahabb are two words with one meaning, according to the terminology of the fuqaha’.
Some of them differentiate between them.
Shaykh Ibn ‘Uthaymeen (may Allah have mercy on him) said:
What is mustahabb is what is masnoon (Sunnah), which is what is enjoined, but not by way of making it binding to do it, because if it was enjoined by way of making it binding to do it, it would be waajib (obligatory).
The ruling on that which is mustahabb is that the one who does it in compliance with what is prescribed will be rewarded, but the one who does not do it will not be punished. However the reward for doing that which is mustahabb or masnoon is less than the reward for doing that which is obligatory, on the basis of textual and rational evidence.
With regard to the textual evidence, it is the words of Allah, may He be exalted, in the hadith qudsi: “My slave does not draw closer to Me by means of anything dearer to Me than that which I have made obligatory upon him.” So an obligatory prayer of two rak‘ahs is dearer to Allah than a voluntary (naafil) prayer of two rak‘ahs.
With regard to the rational evidence, the fact that Allah has made obligatory actions obligatory indicates that they are more emphatically prescribed, and that the accountable person needs to do them more than he needs to do the voluntary (naafil) actions.
Is there a difference between mustahabb and masnoon?
The answer is that some of the scholars differentiated between them by stating that mustahabb refers to that which is proven by analogy (qiyaas) and masnoon refers to that which is proven by a Sunnah, i.e., by evidence.
But the correct view is that there is no difference between them, and the matter is one of terminology. According to the Hanbalis there is no difference between them, so it makes no difference whether we say “It is mustahabb to wash each part three times when doing wudoo’” or “it is Sunnah to wash each part three times when doing wudoo’”. This is simply the matter of terminology; in other words, if someone were to say in his book, “If I say something is Sunnah, I mean that is it proven by a Sunnah, and if I say that it is mustahabb, I mean that it is proven by analogy (qiyaas),” then he carries on with this terminology, he is not to be denounced for that. End quote from ash-Sharh al-Mumti‘ (6/421)
See also: Kashshaaf al-Qinaa‘ by al-Bahooti (1/87); Nihaayat al-Muhtaaj by ar-Ramli (2/105)
And Allah knows best.