Galatians 4:10

Colossians 2:16-17 NIV
Therefore do not let anyone judge you by what you eat or drink, or with regard to a religious festival, a New Moon celebration or a Sabbath day. These are a shadow of the things that were to come; the reality, however, is found in Christ.

Romans 14:5 NIV
One person considers one day more sacred than another; another considers every day alike. Each of them should be fully convinced in their own mind.