There is nothing wrong with celebrating happy occasions such as marriage, the birth of a child, the return of one who was away, passing exams, getting a job and other regular matters, on condition that that is done at the time it happens and is not repeated, because if it is repeated it becomes an eid or festival, and it is not prescribed for us Muslims to celebrate any festival other than Eid al-Fitr, Eid al-Adha and Jumuah. It is not prescribed to celebrate every year one's birthday or wedding anniversary or graduation from university and the like.
It does not matter if the permissible celebrations happen at the time of Christmas, because they have to do with the event which is the reason for the celebration, and should be done when that event occurs.
Shaykh Ibn Uthaymeen (may Allah have mercy on him) was asked about having parties when completing the Qur'aan or on happy occasions such as passing exams or returning from a trip. Is this regarded as extravagance? I hope you can give a detailed answer concerning this. May Allah reward you with good.
There is nothing wrong with having parties when one who has been away returns or when a student passes exams or when someone gets married and the like, because people do that, not with the intention of worship, and it never occurs to them that they are doing this in order to draw close to Allah. Rather they do that to express joy and happiness for the blessings that Allah has bestowed upon them of achieving what they wanted. There is nothing wrong with these parties; rather what there is concern about is that people may be extravagant in these parties, either by preparing too much food which is often more than is necessary; or by inviting too many people, so they invite hundreds of people to that celebration. Otherwise the basic principle is that there is nothing wrong with celebrating happy occasions, but that is not done as an act of worship or seeking to draw close to Allah, rather they are done to express joy and happiness. And Allah knows best.
End quote from Fataawa Noor ala al-Darb.
It says in his Majmoo Fataawa (9/376): The ruling on celebrating children's birthdays:
It should be noted that everything that is taken as an eid and repeated every week or every year, and is not prescribed in Islam, is an innovation (bidah). The evidence for that is that the Lawgiver prescribed the aqeeqah for the newborn, and did not prescribe anything after that. Taking these eids that are repeated every week or every year means that they are likening them to Islamic festivals. This is haraam and it is not permissible. There are no festivals in Islam apart from the three prescribed festivals: Eid al-Fitr, Eid al-Adha and the weekly eid, which is Friday (Jumuah).
This does not come under the heading of customs and traditions, because it is repeated. Hence when the Prophet (blessings and peace of Allah be upon him) came to Madeenah and found that the Ansaar had two festivals which they used to celebrate, he said: Allah has given you something better than them instead of them: Eid al-Adha and Eid al-Fitr, even though these were part of their customs. End quote.
For more information, see the answer to questions nos. 134163, 12032 and 486.
And Allah knows best.
Reproduced from Islam QA