Read Romans 14:5 Using Other Translations
One man esteemeth one day above another: another esteemeth every day alike. Let every man be fully persuaded in his own mind.
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.
In the same way, some think one day is more holy than another day, while others think every day is alike. You should each be fully convinced that whichever day you choose is acceptable.