At this time of year many churches are busy with carol services, nativity plays, Christmass day services and the like. Very few stop to ask why they do these things. Does God in His Word require these things? If he does not, how do we know whether or not they are acceptable?
The origins of the festival of Christmass in Babylonian paganism in terms of its date and its customs are quite obvious (see Alexander Hislop's study http://philologos.org/__eb-ttb/sect31.htm). The Encyclopedia Britannica makes this clear "In the south of Europe, in Egypt and Persia, the sun gods were worshipped with elaborate ceremonies at the season of the winter solstice, as a fitting time to pay tribute to the benign god of plenty, while in Rome the Saturnalia reigned for a week. In northern lands mid-December was a critical time, for the days became shorter and shorter and the sun was weak and far away. Thus these ancient peoples held feast at the same period that Christmas is now observed." (1961 ed.), 5:643.
Christmass was not celebrated by the apostles or the early church. It was not until the middle of the 4th century, that many churches in the Latin west celebrated Christmass and during the 5th century, Christmass became an official Roman Catholic holy day. The Roman Catholics of that time believed in bringing pagans into the Church by "Christianizing" their pagan religious customs and practices. They simply transferred the symbols of the worship of pagan gods and gave them a Christian significance. Although a successful "missionary strategy" outwardly it was in direct rebellion against God who commands: "Learn not the way of the heathen, and be not dismayed at the signs of heaven; for the heathen are dismayed at them. For the customs of the people are vain" (Jer. 10:2-3). "Thou shalt not do so unto the LORD thy God: for every abomination to the LORD, which he hateth, have they done unto their gods" (Deut. 12:31).
Even if Christmas had no pagan associations of the past or with Roman Catholicism we ought to reject it because the Bible does not teach the observance of Christmas. The Scriptures make it clear exactly how we are to worship God, including special days that we should observe, “what thing soever I command you, observe to do it; thou shalt not add thereto, nor diminish from it”. (Deut. 12:32 cf Lev. 10:1-3). For other Scriptures maintaining this principle see: Genesis 4:3-5; 2 Samuel 6:3-7 and 1 Chronicles 15:13-15, cp. Numbers 4:6 and 15. The second commandment teaches us that we are only to worship God in the way that He requires. Answer 109 of the Westminster Larger Catechism explains that the commandment forbids "any other wise approving, any religious worship not instituted by God himself." The teaching of the Lord Jesus Christ reinforces this: - “In vain do they worship me, teaching for doctrines the commandments of men. For laying aside the commandment of God, ye hold the tradition of men” (Mark 7:7-8). The Apostle Paul likewise warns against “will worship” (Col. 2:22-23), worship that originates in the wishes of man wants to do rather than the commandment of God.
The Lord Jesus Christ commands the Church to teach men to observe all things that He had commanded (Matt. 28:20). They had no authority to add or take from what He has commanded. This scriptural teaching that whatever Scripture does not command is to be excluded from worship is known as the "regulative principle”. We exclude uninspired hymns, musical instruments and also holy days appointed by man. It is of course appropriate to respond to the providence of God with days of thanksgiving or prayer and humiliation as the Westminster Directory For Public Worship explains: “Nevertheless, it is lawful and necessary, upon special emergent occasions, to separate a day or days for public fasting or thanksgiving, as the several eminent and extraordinary dispensations of God’s providence shall administer cause and opportunity to his people” (Westminster Directory For Public Worship), it goes on to say, however, that, “festival days, vulgarly called ‘Holy-days’, having no warrant in the Word of God, are not to be continued”.
While events and situations in providence vary across the years and century and across nations, the facts of the redemption that has been accomplished do not. The death and resurrection of Christ are commemorated through the Lord's Supper and the Lord's Day. No other days have been appointed and therefore they are not needed. To appoint other days is to reject the wisdom of God, believing that His appointment was insufficient.
King Jeroboam of Israel violated the regulative principle by ordaining a holy day “which he had devised of his own heart” (1 Kings 12:32-33). It was similar to the one that God had ordained and it was in worship of the same God but it was not on the day that God had commanded but on a day of Jeroboam’s devising.
v32 And Jeroboam ordained a feast in the eighth month, on the fifteenth day of
the month, like unto the feast that is in Judah, and he offered upon the altar. So did he in Bethel, sacrificing unto the calves that he had made: and he placed in Bethel the priests of the high places which he had made.
v33 So he offered upon the altar which he had made in Bethel the fifteenth day
of the eighth month, even in the month which he had devised of his own heart;
and ordained a feast unto the children of Israel: and he offered upon the altar,
and burnt incense.
Some may appeal to the feast of Purim in the book of Esther. The feast of Purim was not, however, worship as Esther 9:18, 26, and 28 makes clear. It was a day of gladness, but not an institution of worship like Jeroboam’s sacrifices. The Westminster Confession speaks of “solemn fastings, and thanksgivings upon special occasions, which are, in their several times and seasons, to be used in an holy and religious manner.” (WCF Chapter 21, Section 5). It uses Esther 9:20-22 as a proof text for “and thanksgivings upon special occasions”, not for the ordinances of worship which it deals with before this.
For an excellent study of this matter see The Regulative Principle of Worship and Christmas by Brian Schwertley