[Sons to Glory!]

Originally Posted by Zezima

At the very least your salvation, your membership to the new creation, have nothing to do with your participation in this holiday.

And it's really just a cultural thing, a minor thing, like Paul addresses with these two verses:

Colossians 2:16
Therefore let no one pass judgment on you in questions of food and drink, or with regard to a festival or a new moon or a Sabbath.

Romans 14:5-6
One person esteems one day as better than another, while another esteems all days alike. Each one should be fully convinced in his own mind. The one who observes the day, observes it in honor of the Lord. The one who eats, eats in honor of the Lord, since he gives thanks to God, while the one who abstains, abstains in honor of the Lord and gives thanks to God.