All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His Slave and Messenger.
In fact, Black Friday is not just a shopping day; rather, it is a festival (‘Eed) celebrated by non-Muslims. The Arabic word ‘Eed is derived from "‘awd” meaning “come again”.
Shaykh Al-Islam Ibn Taymiyyah defined ‘Eed as follows: "The Arabic word ‘Eed means in the Arabic language what recurs of public events in a traditional manner; it may recur every year, month, or week or so. Therefore, the word ‘Eed refers to a day that comes again like ‘Eed Al-Fitr or Jumu‘ah, the gathering on that day and the acts done as acts of worship or traditions on that day. It may or may not be peculiar to a certain place. Any such gathering that takes place regularly can be called ‘Eed." Therefore, Black Friday is considered one of the ‘Eeds of the disbelievers.
Participating in the celebration of the festivals of the non-Muslims by any given means involves committing religious violations, some of which were highlighted by Shaykh Al-Islam Ibn Taymiyyah as he said:
"With regard to things that they use in their festivals, such as food, drink and clothing, the principles of Imaam Ahmad and others suggest that it (selling such things) is disliked, but does disliked here mean that it is prohibited, as in the School of Maalik, or that it is merely discouraged? The most likely and preponderant view is that it is disliked in the sense of being prohibited as in many similar cases according to Ahmad, because he does not allow the sale of bread, meat and herbs to the dissolute who will drink wine with them, because these things assist them to manifest the false religion and increase the numbers of people who will gather on their festival. This is worse than helping one particular person."
Allaah The Exalted says (what means): {And cooperate in righteousness and piety, but do not cooperate in sin and aggression. And fear Allaah; indeed, Allaah is severe in penalty.} [Quran 5:2]
Based on this, it is impermissible for the Muslim to take part in this ‘Eed or help others celebrate it by partaking in any commercial promotion that is particularly targeting that day; rather, he should treat it like any other day of the year.
Allaah Knows best.