Celebration of any historical or current or future event is legitimate and righteous as long as such a celebration is not forbidden by God in principle and the celebrations use holy methods and means. Moreover, just because some people may use unholy methods and means regarding the celebration does not invalidate the celebration for those using holy methods and means.
Such events may be of a religious or non-religious nature. They may be private or public.
People may choose to participate in a particular celebration or they may choose to not participate according to their particular religious or non-religious beliefs and convictions and goals.
Birthday celebrations are legitimate and righteous as God does not command they not be held.
Religious holydays listed in Leviticus 23 are legitimate and righteous for both Jews and Gentiles as God does not forbid Gentiles from participating in them. Circumcision laws do not apply to participation in a feast including Passover under the New Covenant under Christ per Acts 15. The fact that according to Acts 15 Christ is an uncircumcised believer Passover ought to make it clear that circumcision is not required to participate in the Mosaic Passover under Christ. Purification laws also do not apply since it is that which comes from the heart that defiles a person under Christ per Matthew 15:10-20. Examples of such feasts include Passover and Feast of Weeks also known as Pentecost. This also includes the Weekly Sabbath feast. For it is still good for every person to not work seven days a week on a regular basis but rather to take at least one day off regularly each week to focus away from natural work to worship, physical rest, and spiritual work. For such is a matter of faith that God will provide for us naturally on at most six days of work. Also, keeping the feasts even for those fulfilled by Christ is good to do. This is so even if the feasts are kept only in the spirit of the law rather than the letter (as written) of the law per 2 Corinthians 3:6; Romans 7:6. It is good to do even if one is not able to keep every element of the written law for some reason and even if others are able to keep different elements for some reason. It is good to do to recognize and commemorate the purpose of the feasts and what Christ fulfilled regarding the fulfilled feasts and what yet is to be done regarding the unfulfilled feasts. This is good to do keeping in mind Colossians 2:14-17 which exhorts us not to judge one another regarding such weekly sabbaths and annual feasts and new moons.
Religious holidays not listed in Leviticus 23 are legitimate and righteous for God does not forbid them. Examples are Hanukkah and Purim
Religious celebrations not listed in the Bible are legitimate and righteous as God does not restrict religious holidays or other religious celebrations to those listed in scriptures. Examples are Easter and Christmas.
National Government celebrations are legitimate and righteous as God does not forbid them. Examples are Presidents Day, Black History Month, Memorial Day, Juneteenth, 9-11 Memorial, Independence Day or July 4th, Labor Day, Veterans Day, and Thanksgiving.
Other societal celebrations are legitimate and righteous as God does not command they not be held. Examples include New Year’s Day, Valentines Day, Mother’s Day, and Father’s Day.
Now let me speak to those who claim that the feasts listed in Leviticus 23 and the feasts of Hanukkah and Purim are the only legitimate and righteous celebrations. In the below, when I speak of immaturity, I speak of a failure to rightly divide the word of truth regarding the particular matters though a person might be mature on other matters. Such immaturity reflects ignorance as in being uninformed, and/or dishonesty as in lacking integrity. Sometimes dishonesty is a result of the fact that the truth goes against the doctrines of the group to which a person belongs and the person lacks the faith and courage to challenge the group with the newly discovered truth. Therefore, he or she rejects the truth.
Firstly, it is spiritual and intellectual immaturity to not recognize that if God does not forbid a thing explicitly or in principle then it is legitimate and righteous to do that thing as long as holy methods and means are used.
Secondly, it is spiritual and intellectual immaturity to claim that because a celebration is done on a day that something evil was done makes a thing illegitimate and unholy. For if one looks far and long enough something evil has probably been done on every day of the week, month, year.
Thirdly it is spiritual and intellectual immaturity to claim that because the name of a celebration may have come from a pagan god or goddess then that makes the celebration illegitimate and unrighteous. For even God told Gideon in Judges 6:25-26 to repurpose the wood from an idol goddess and use it in a holy sacrifice. Therefore, even if a name of a celebration comes from a pagan god or goddess, the repurposing of that name to honor God is legitimate and righteous. Therefore, Easter is legitimate and righteous.
Fourthly, it is spiritual and intellectual immaturity to claim that the use of a decorated tree for gifts is illegitimate and unrighteous. The same applies to the claim that the actual birthdate of Christ is not known to actually be December 25th. For certainly wood from trees as well as silver and gold was used in building and decorating the Temple as instructed by God per 1 Kings 6:9, 15, 22, 31. For only when trees are used for idol worship are their use forbidden. Certainly, a Christmas tree is used to honor the birth of the Son of God. Any adult who claims that is idol worship lacks spiritual and intellectual integrity for certain. For no adult can be that intellectually ignorant. As to the birthdate claim, certainly the Bible does not give the date of Christ birth. But Christmas is not about the date but is about the birth. It is similar to a person’s birthdate in a given year falling on a Wednesday. Yet, he delays the birthday party until the weekend. He is able to do so with integrity because he and his family and friends are celebrating the fact he was born not the date he was born. Therefore, Christmas is legitimate and righteous.
Fifthly, it is spiritual and intellectual immaturity to claim that the Lord’s Supper is Passover. Certainly it was at Jesus last Mosaic Passover before crucifixion that he instituted the Lord’s Supper so named from the words in 1 Corinthians 11:20. The name is Lord’s Supper; the name is not Last Supper as there is a profound difference. Either Jesus in Matthew 26:26-28; Mark 14:22-24; and Luke 22:19-20 completely changed the purpose of the Mosaic Passover as given in Exodus 12:14, 24-27, 42; or he instituted something completely new. Indeed, Jesus instituted something completely new and different from the Mosaic Passover. For what Jesus instituted was in remembrance of him not what God did in bringing the Israelites out of Egypt. Indeed, 1 Corinthians 11:26 says: “For as often as ye eat this bread, and drink this cup, ye do shew the Lord’s death till he come.” So then the Lord’s Supper is clearly about Christ crucifixion where his body (the bread) was bruised unto death and his blood (the cup) shed for the remission of sins. That is not the Mosaic Passover although the Mosaic Passover was a type or foreshadowing of what Christ would one day do. Hence 1 Corinthians 5:7 says Christ is our Passover lamb. He is not the lamb one kills and eats annually for the Mosaic Passover. But he is the lamb crucified once as Hebrews 9:28; 10:10-12 says. It is his once for all death we memorialize weekly, monthly or as often as one pleases in the form of the Lord’s Supper, also known as Communion.
Sixthly, it is spiritual and intellectual immaturity for the early church to have transferred the Sabbath functions of holy convocation and rest from Saturday to Sunday. Indeed, church leaders at the Synod of Laodicea in the 4th Century AD admitted in written canons that at least as early as the 4th Century AD they believed Saturday was the biblical Sabbath. The fact they transferred the holy convocation to Sunday and required their people to rest on Sunday instead of Saturday, excommunicating those who rested on Saturday, clearly shows even they believed there is still a need for the Sabbath. They later rescinded the excommunication provision upon realizing it was wrong. Indeed, the Sabbath is a matter of faith that God will provide if a person works at most six days a week on a regular basis; it is still needed. Indeed, they could have easily and non-problematically honored Jesus resurrection on the biblical Sabbath even though they believed Jesus resurrected on the first day of the week. For after all Jesus did say he is Lord of the Sabbath.
Seventhly, it is spiritual and intellectual immaturity for the early church to have aligned Easter conceptually with the Leviticus 23 Feast of First Fruits and Pentecost 50 days from Easter but not aligned Easter with Feast of First Fruits Hebrew calendar wise. If they had aligned Easter with the Feast of First Fruits Hebrew Calendar wise that would have also aligned Pentecost with the Leviticus 23 Feast of Weeks which is 50 days from the Feast of First Fruits. After all, Pentecost of the New Testament is Feast of Weeks of the Old Testament, different names for the same event conceptually though not aligned calendar wise. Proper alignment would also promote recognition of Passover and Feast of Unleavened Bread, both which should be non-problematic. Unfortunately, their chosen course has erected an artificial wall of separation and disunity between Jew/Israelite Christians and Gentile Christians, a wall which Christ removed the necessity for per Ephesians 2:11-22 and Hebrews 10:19-20. They took the desire to avoid Judaizing too far.