It does seem notable that arguably the greatest continental Reformed theologian contemporary to Westminster era Puritanism took a relatively moderate stance on the observance of festivals.
Taken from a recent article written by Andrew Myers entitled "Nadere Reformatie Contra Christmas" (complete article here:
Virginia is for Huguenots: Nadere Reformatie Contra Christmas)
...
The conclusion that the toleration and promotion of the man-made ecclesiastical calendar (including even Saint Nicholas Day) is good for piety was not shared, however, by the Nadere Reformatie, which sought to limit the observation of such holidays to that alone which had warrant from Scripture -- the Lord's Day, and occasional extraordinary days of fasting and thanksgiving -- as will be seen by these quotes from leading representatives of the movement.
Willem Teelinck, The Path of True Godliness, p. 101:
[Rules that help distinguish between truth and lies, walking in divine truth promotes godliness] For example when debating whether to maintain Lenten Eve (Fat Tuesday), Epiphany (when the wiseman saw Christ), and other Roman Catholic holidays or to radically abolish them, some people may say yes and others no. However, the godly immediately know the right way, for they understand that Roman Catholic holidays have no basis in Holy Scripture and that regular observance of them offers occasion for much sin. The celebrations cause great disorder in the places or homes where they are observed and become a stumbling block to real holiness as they strengthen the old man. The godly swiftly conclude that Reformed Christians who would gladly abolish or ignore the feast days have the truth on their side.
Jacobus Koelman (who, it is reported, coined the term 'Nadere Reformatie'), The Duties of Parents, p. 73:
100. Do not allow your children to celebrate the days on which unbelief and superstition are being catered to. They are admittedly inclined to want this because they see that the children of Roman Catholic parents observe those days. Do not let them attend carnivals, observe Shrove Tuesday (Mardi Gras), see Santa Claus, or observe Twelfth Night, because they are all remnants of an idolatrous papacy. You must not keep your children out of school or from work on those days nor let them play outside or join in the amusement. The Lord has said, "After the doings of the land of Egypt, where you lived, shall ye not do: and after the doings of the land of Canaan, where I bring you, you shall not do: neither shall you walk in their ordinances" (Lev. 18:3). The Lord will punish the Reformed on account of the days of Baal (Hosea 2:12-13), and he also observes what the children do on the occasion of such idolatry (Jer. 17:18). Therefore, do not let your children receive presents on Santa Claus day, nor let them draw tickets in a raffle and such things. Pick other days on which to give them the things that amuse them, and because the days of Christmas, Easter, and Pentecost have the same character, Reformed people must keep their children away from these so-called holy days and feast days.
Wilhelmus à Brakel, The Christian's Reasonable Service, Vol. I, pp. 38-39:
Objection #4:
The Jewish church also instituted various practices passing them on to subsequent generations which nevertheless were not commanded, such as fasting in the fourth, fifth, seventh, and tenth month (Zec. 7:5 and 8:19); the days of Purim (Est. 9:21-26); the feast of the dedication (John 10:22). In similar fashion the Reformed Church also has her traditions, which implies that also now we may and must uphold tradition.
Answer:
The practice of fasting was commanded by God; the determination of necessity, time, and circumstances was left to the church (Joel 2). Special days of thanksgiving are also commanded, the occurrence and frequency of which are to be determined by the church. There is no basis in the Word, however, upon which the church may legislate the observation of such days for subsequent generations. Such practices should be denounced and the church should not observe them. This is true also for our so-called feast days which ought to be eliminated. Regarding feast days consult Res Judicata by [Jacobus] Koelman, as well as his other scholarly and devotional writings. Other external religious ordinances and circumstances are principally commanded in the Word of God, the stipulations of which are left to each individual church, and consequently are alterable according to time and place. In doing so, however, all superstition must be avoided and such practices must not have an adverse effect upon doctrine and practice. Thus, the perfection of the rule of Scripture will not be violated, nor will the use of unwritten traditions be advocated.
