Valentine day

In Islam, the festivals are clearly defined and well established, and no additions or subtractions may be accepted. They are an essential part of our worship and there is no room for personal opinion. They have been prescribed for us by Allah and His Messenger sallallaahu `alayhi wa sallam ( may Allah exalt his mention ). Ibn Taymiyyah, may Allah have mercy on him, said: "Festivals are part of the laws, clear way and religious ceremonies of which Allah Says (what means): 'To each among you, We have prescribed a law and a clear way' [Quran 5:48] and 'For every nation We have ordained religious ceremonies which they must follow.'" [Quran 22:67]

Like the Qiblah (the direction faced in prayer), prayer and fasting. So there is no difference between joining them in their festival and joining them in their other rituals. Agreeing with the whole festival is agreeing with disbelief. Agreeing with some of their minor issues is the same as agreeing with them in some of the branches of disbelief.

Festivals are the most distinctive things by which religions are told apart, so whoever celebrates their festivals is agreeing with the most distinctive rituals of disbelief. Undoubtedly, going along with them in their festivals may, in some cases, lead to disbelief. Dabbling in these things, at the very least, is a sin. The Prophet sallallaahu `alayhi wa sallam ( may Allah exalt his mention ) referred to the fact that every nation has its own festivals when he sallallaahu `alayhi wa sallam ( may Allah exalt his mention ) said: "Every nation has its own ‘Eed and this is our ‘Eed." [Al-Bukhari]