Valentine's Day
In his law to the nation of Israel, God declared: “You must not mention the name of other gods. It should not be heard upon your mouth.” (Ex. 23:13) This meant that the Israelites were not to refer to false gods with feelings of awe or in a way that would credit them with any existence or power. They were to regard such false gods with contempt, as valueless, shameful, detestable and disgusting.-Ps. 96:5; Jer. 11:13; Ezek. 16:36; 37:23.
As for any of the religious appendages associated with the false worship of the Canaanites, the Israelites were instructed: “Their altars you should pull down, and their sacred pillars you should break down, and their sacred poles you should cut down, and their graven images you should burn with fire. For you are a holy people to Jehovah your God.”-Deut. 7:5, 6.
The unchangeable God, Jehovah, is no more tolerant of idolatrous practices today than he was in the past. (Mal. 3:5, 6) The Christian apostle Paul reminded fellow believers: “What fellowship do righteousness and lawlessness have? Or what sharing does light have with darkness? Further, what harmony is there between Christ and Belial? Or what portion does a faithful person have with an unbeliever? And what agreement does God’s temple have with idols? For we are a temple of a living God; just as God said: ‘I shall reside among them and walk among them, and I shall be their God, and they will be my people.’ ‘“Therefore get out from among them, and separate yourselves,” says Jehovah, “and quit touching the unclean thing.”’”-2 Cor. 6:14-17.
Concerning Valentine’s Day, The World Book Encyclopedia (1973 edition) notes:
“Valentine’s Day comes on the feast day of two different Christian martyrs named Valentine. But the customs connected with the day have nothing to do with the lives of the saints. They come from an ancient Roman festival called Lupercalia which took place every February 15. The festival honored Juno, the Roman goddess of women and marriage, and Pan, the god of nature.”
But how did a festival in honor of false deities become a so-called Christian observance? The same reference work continues:
“After the spread of Christianity, churchmen tried to give Christian meaning to the pagan festival. In 496, Pope Gelasius changed the Lupercalia festival of February 15 to Saint Valentine’s Day on February 14. But the sentimental meaning of the old festival has remained to the present time."
Basically, as with practically every other holiday, previous pagan holidays were given a "christian" label on them, but the same pagan rituals are mostly practiced till this day. God, however, makes it known in the bible that Christians should never partake in anything unclean nor anything that would constitute a form of worshipping another god.