Festivals ...
Why should we not celebrate Valentines, Mother's Day, etc.

Muslims are advised to distinguish themselves in their external appearance adopting Islamic ways and methods in all their affairs, whether worldly or Deeni. By this, it is meant that Muslims are recognised and identified by a single religious culture or code, which is purely Islamic. Islam prohibits adoption of the ways and appearance of other beliefs, cultures, customs and nations. Therefore it is very essential that Muslims guard themselves against assimilation into other non-Muslim cultures. The external appearances of Muslims may be classified under the following points:

1. Acts that eliminate a Muslim's identity which are obviously Haraam even if they are not the special characteristic of other communities such as wearing shorts (thus exposing the satr), etc. are forbidden.
2. Acts that are prohibited to imitate because it is alien to a nation or community. For example, to eat sitting at tables with knives and forks. This manner of eating is contrary to the Sunnah. Similarly, ways adopted from the non-Muslims that are of religious significance like wearing the cross, celebrating Christmas, etc. would amount to Kufr.
3. Acts that are not exclusive to any particular community. The adoption of such acts will be permissible, like dressing as long as the satr is covered. However, this does not apply to a specific religious garb.
4. Acts that have neither religious nor cultural significance. Such things are of real value and benefit even if they are inventions of the non-Muslims; there is nothing wrong in adopting them. For example, transport, technology, communications, weapons and other things of benefit. However, if Muslims have their own equivalent, then they should make use of their own products and not give preference to the products of the non-Muslims.
5. Islam also prohibits Muslims to imitate "Muslims" (Faasiqs and Faajirs) who openly flout the Laws of Allah like shaving the beard (for men).

Undermentioned are a few verses of the Holy Qur’an and Ahaadith pertaining to the subject matter:

1. ‘Do not incline to the transgressors for then the Fire will touch you.’ (Surah Hood 113)
   
   The above ayat sufficiently warns Muslims not to adopt or imitate the culture and customs of the non-Muslims.
2. Shaitaan said, ‘...I will teach them to ruin the appearance made by Allah....’(Surah Nisaa 119)
   
   Appearance by virtue of customs is subjected to change with the times and attitudes of people, but this is not so in the Shariah. Shaitaan will always be on the `backs' of people to renovate their thinking to `live with the times'.
3. Hadhrat Ibn Umar (Radhiyallaahu Anhu) reports that Rasulullah (Salallaahu Alaihi Wasallam) said, `Whoever imitates a nation (in its ways and culture) becomes one of them.' (Abu Dawood)
   
    By adopting even the appearance of the non-Muslims, that in itself is association with them and is therefore sinful.
4. Hadhrat Abu Raihaanah (Radhiyallaahu Anhu) narrates that once Rasulullah (Salallaahu Alaihi Wa Sallam) prohibited ten things. Among these ten things prohibited was to line garments with silk in the style of the non-Muslims (of that time).(Abu Dawood, Nisaai)
5. Hadhrat Hajjaj Bin Hassaan (Radhiyallaahu Anhu) narrates: "We went to meet Hadhrat Anas (Radhiyallaahu Anhu) (a prominent Sahaabi; on this occasion Hajjaj was a little boy). My sister Mugheera told me that at that time I was a little kid and I had two plaits on my head. Hadhrat Anas (Radhiyallaahu Anhu) rubbed his hand over my head, made Dua for barakat and said: 'Cut off these plaits because this is the style of the Jews.' (Abu Dawood)
6. Hadhrat Aamir Bin Sa'd (Radhiyallaahu Anhu) narrating from his father says that Rasulullah said: "Maintain clean the area in front of your houses and do not imitate the Jews."(Tirmizi)
7. Hadhrat Ali (Radhiyallaahu Anhu) narrates that once Rasulullah (Sallallaahu Alayhi Wasallam) had an Arabian crossbow in his hand. On this occasion Rasulullah (Salallaahu Alaihi Wasallam) saw a crossbow of Persian origin in the hands of a Muslim. Rasulullah (Salallaahu Alaihi Wasallam) commented: "Throw it (the Persian bow) away and take one like this (Arabian bow)..."(Ibn Majah)
8. Hadhrat Huzaifah (Radhiyallaahu Anhu) narrates that Rasulullah (Sallallaahu Alayhi Wasallam) said: "Recite the Qur’an in Arabic style and tone (i.e. correct and with simplicity) and refrain from the style and tone of the People of the Book (Jews and Christians...)" (Baihaqi)

Rasulullah (Salallaahu Alaihi Wa Sallam) went to great lengths disapproving the imitation of non-Muslims even in the recitation of the Noble Qur’an as mentioned in the last Hadith (above). Hence nations that do not follow the Shariah should not be imitated. Therefore any act, be it the celebration of a particular community that may or may not necessary be religious, but merely associated to their "way of rejoicing" falls under the same banner - imitating the non-Muslims. The question of Mother's Day, Father's Day, Valentine's Day, etc. may be categorised under one of the classifications mentioned earlier in our discussions.