Is it allowed to sell gifts specifically for the occasion of the Christian festivals?
“Which gifts? As for selling general things on the day of their festival, then there is no harm. Selling them (such as) food, fruit, such and such. There is no problem in this. As for specific things, this requires some explanation. Yes”.
Also Shaikhul Islaam Ibn Taymiyyah rahimahullah said:
“All praise is due to Allah. It is not permissible for the Muslims to resemble them [the disbelievers] in something that is specific to their festivals. Not in food, clothing, washing, lighting a fire, or a custom in life or worship or other than that. It is not allowed to have a banquet, or give a gift, nor sell what will aid them in that [celebration] due to that [celebration]. It is not allowed to give the children and the likes toys which are in the festival nor that makes apparent adornment [for that celebration]…and they said [the Scholars]
“They said: [the Scholars]: it is not allowed for Muslims to sell Christians something that benefits their festival. Not meat, blood, clothes, nor borrowing a riding animal, nor aid them in something in their religion. That is because it venerates their shirk and aiding their disbelief. It is necessary for the rulers to prevent the Muslims from that because Allah, the Exalted said:
وتعاونوا على البر والتقوى ولا تعاونوا على الإثم والعدوان
Help you one another in Al-Birr and At-Taqwa (virtue, righteousness and piety); but do not help one another in sin and transgression.
[Majmoo’ al-Fatawa (15/330-332)]
Faisal Ibn Abdul Qaadir Ibn Hassan