Customs as long as they don’t interfere with obedience to the Word of God are not a problem. The danger occurs when we allow customs to be intermixed with or even to replace the doctrines that the apostles gave. I don’t suppose that Celtic customs are any more likely to do that than any other kind.
The Celtic religion is a pagan religion and thus the customs of that religion like any other non-Christian religion should be shunned. We should never allow the customs or traditions of men to interfere with our obedience to God whether it be a family tradition, a religious doctrine, or a national, ethnic, or cultural custom.
Some Celticisms that we should watch out for are Easter, Christmas trees, and St. Patrick’s Day. Although all of these things have become associated in one way or another with religious activity, we need to watch out that they don’t get in the way of the truth. I am not saying that we should not have anything to do with these three things or any other custom as long as it does not cause sin. We must, however, remember that these pagan oriented traditions have no more place in our assemblies than do Halloween, Valentine’s Day, or July 4. The time that we are assembled together is a special time set aside for praising God in song, studying His Word, praying, observing the Lord’s Supper, giving of our means, and exhorting and encouraging our fellow Christians.
We don’t need to celebrate Easter as a religious holiday (holy day), but if we enjoy hunting Easter eggs and giving candy that is all good and fun. We remember Christ’s resurrection each week when we partake of the Lord’s Supper, and that is sufficient. Christmas trees are fun to decorate, pretty to look at, and a good place to store presents, and there is nothing sinful in that. There have been sins associated with trees in times past, and the custom does come from a pagan form of worship, but as long as we recognize God’s creative power and don’t fall to worshiping the created rather than the Creator we are not sinning with them. (Jer 10:3-5) “For the customs of the people are vain: for one cutteth a tree out of the forest, the work of the hands of the workman, with the ax. {4} They deck it with silver and with gold; they fasten it with nails and with hammers, that it move not. {5} They are upright as the palm tree, but speak not: they must needs be borne, because they cannot go. Be not afraid of them; for they cannot do evil, neither also is it in them to do good.” Jeremiah points out the sin of worshiping or attributing some special powers to a tree, but not the use of it as decoration.
(Gal 4:8-11) “Howbeit then, when ye knew not God, ye did service unto them which by nature are no gods. {9} But now, after that ye have known God, or rather are known of God, how turn ye again to the weak and beggarly elements, whereunto ye desire again to be in bondage? {10} Ye observe days, and months, and times, and years. {11} I am afraid of you, lest I have bestowed upon you labour in vain.” Paul makes it clear to the Galatians that there is only one God and only the commandments that He makes are to be heeded. If we like these Galatians observe all of these “holidays” and think that we are in some way better for it, we are mistaken. They are fun and enjoyable, and we get to be with family, but there is nothing HOLY about our Holidays.
There are many that use these traditional gatherings as well as others like family reunions as an excuse to miss the assembly of the saints. When we allow that to happen we have sinned. Let us put forth every effort to observe God’s Holy will and not man’s holy days.