Muslims preparing a turkey dinner on Thanksgiving Day

It is forbidden for a Muslim to prepare a turkey dinner on Thanksgiving because this is an imitation of non-Muslims. It is confirmed in an authentic narration that whoever imitates a people is one of them.

Saying that the family gathers on this day and this is not with the purpose of imitating the non-Muslims but due to the fact that this day is a holiday, then this does not make it permissible for you to do this, because in essence you are imitating them. Gathering on this day could be on any other kind of food, why then have specifically a turkey dinner? Is this not imitating them even in the kind of food they eat?

The prohibition of resembling the non-Muslims is not restricted to inward actions [beliefs, actions of the heart] and intentions, but also to outward actions. It is for this reason that the Prophet prohibited us from performing the prayer at sun set and sun rise, and he  said that it rises between two horns of the devil and the polytheist prostate to it at this time, despite the fact that a Muslim prays to Allah and not to the horns of the devil. However, the Prophet  forbade us from performing the prayer at that time regardless of our intention.

The Prophet also used to differ from the people of the book even in the way they combed their hair.

Indeed, there are many narrations of the Prophet  about differing from the people of the Book in regard to both words and actions.

Therefore, we advise you to fear Allah and not imitate the polytheists and act in conformity with them in their festivals and traditions which are peculiar to them.

Dear sister, you should advise your brothers and sisters with wisdom and in a good and soft manner as they might listen to you. You should explain to them that it is permissible for the family to gather on that day because it is a holiday but without making this day as a festival and imitating the non-Muslims in their eating traditions and the like. It should be a family gathering like all other gatherings throughout the year [without any special food, settings or decorations].

https://www.islamweb.net/en/article/155839/muslims-preparing-a-turkey-dinner-on-thanksgiving-day

Ruling on celebrating non-Muslim holidays and congratulating them

Greeting the kuffar on Christmas and other religious holidays of theirs is haram, by consensus, as Ibn al-Qayyim, may Allah have mercy on him, said in Ahkaam Ahl al-Dhimmah: "Congratulating the kuffar on the rituals that belong only to them is haram by consensus, as is congratulating them on their festivals and fasts by saying ‘A happy festival to you’ or ‘May you enjoy your festival,’ and so on. If the one who says this has been saved from kufr, it is still forbidden. It is like congratulating someone for prostrating to the cross, or even worse than that. It is as great a sin as congratulating someone for drinking wine, or murdering someone, or having illicit sexual relations, and so on. Many of those who have no respect for their religion fall into this error; they do not realize the offensiveness of their actions. Whoever congratulates a person for his disobedience or bid’ah or kufr exposes himself to the wrath and anger of Allah."

Congratulating the kuffar on their religious festivals is haram to the extent described by Ibn al-Qayyim because it implies that one accepts or approves of their rituals of kufr, even if one would not accept those things for oneself. But the Muslim should not accept the rituals of kufr or congratulate anyone else for them, because Allah does not accept any of that at all, as He says (interpretation of the meaning): "If you disbelieve, then verily, Allah is not in need of you, He likes not disbelief for His slaves. And if you are grateful (by being believers), He is pleased therewith for you. . ." [al-Zumar 39:7]

"... This day, I have perfected your religion for you, completed My favor upon you, and have chosen for you Islam as your religion ..." [al-Maa’idah 5:3]

So congratulating them is forbidden, whether they are one’s colleagues at work or otherwise.

If they greet us on the occasion of their festivals, we should not respond, because these are not our festivals, and because they are not festivals which are acceptable to Allah. These festivals are innovations in their religions, and even those which may have been prescribed formerly have been abrogated by the religion of Islam, with which Allah sent Muhammad (peace and blessings of Allah be upon him) to the whole of mankind. Allah says (interpretation of the meaning): "Whoever seeks a religion other than Islam, it will never be accepted of him, and in the Hereafter he will be one of the losers." [Aal ‘Imraan 3:85]

It is haram for a Muslim to accept invitations on such occasions, because this is worse than congratulating them as it implies taking part in their celebrations.

Similarly, Muslims are forbidden to imitate the kuffar by having parties on such occasions, or exchanging gifts, or giving out sweets or food, or taking time off work, etc., because the Prophet (peace and blessings of Allah be upon him) said: "Whoever imitates a people is one of them." Shaykh al-Islam Ibn Taymiyah said in his book Iqtidaa’ al-siraat al-mustaqeem mukhaalifat ashaab al-jaheem: "Imitating them in some of their festivals implies that one is pleased with their false beliefs and practices, and gives them the hope that they may have the opportunity to humiliate and mislead the weak."

Whoever does anything of this sort is a sinner, whether he does it out of politeness or to be friendly, or because he is too shy to refuse, or for whatever other reason, because this is hypocrisy in Islam, and because it makes the kuffar feel proud of their religion.

Allah is the One Whom we ask to make the Muslims feel proud of their religion, to help them adhere steadfastly to it, and to make them victorious over their enemies, for He is the Strong and Omnipotent. Majmoo’ah Fataawa wa Rasaa’il al-Shaykh Ibn ‘Uthaymeen, 3/369)

https://islamqa.info/en/answers/947/ruling-on-celebrating-non-muslim-holidays-and-congratulating-them

Eating from a Thanksgiving meal

That is permissible, because food is respectable and pure, and that is better than throwing it away. It is permissible to eat the food of the Christians because Allah says (interpretation of the meaning): “The food (slaughtered cattle, eatable animals) of the people of the Scripture (Jews and Christians) is lawful to you and yours is lawful to them” [al-Maa’idah 5:5]

So there is nothing wrong with that. Their bread, their food, and whatever dishes and sweets etc. they cook are all good and pure, and there is nothing wrong with them. But if the food has been made for that celebration, it is not permissible to be there at the time of the party, but after the party it is permissible to eat the food and that is better than throwing it away.

https://islamqa.info/en/answers/13739/eating-leftovers-from-a-thanksgiving-meal-so-that-it-will-not-be-thrown-away

Ruling on buying clothing and other items during kaafir festivals in order to benefit from discounts on prices during the Christmas season

There is nothing wrong with buying clothing, furniture and so on during the seasons of kafir festivals such as Christmas, on condition that one does not buy things that are used to celebrate the festival or to imitate the kuffar during their festivals.

It is permissible for the Muslim to open his business during the days of kafir festivals, subject to two conditions:

(i) That he does not sell them things that they use for sinful purposes or to celebrate their festival.

(ii) That he does not sell to Muslims things that they may use to imitate the kuffar during these festivals.

Buying items that one need is much less serious than selling or opening one's business and the basic principle is that it is permissible to buy things, and the fact that it happens at the time of their festival does not matter.

https://islamqa.info/en/answers/145676/ruling-on-buying-clothing-and-other-items-during-kaafir-festivals-in-order-to-benefit-from-discounts-on-prices-during-the-christmas-season