Do Christians still have to keep the 7th-day Sabbath?
Christians are not obligated to keep any day as the Sabbath because we are not under the Mosaic Law. Rather, we are to celebrate the Lord’s day, and we can do so on whichever day we choose (see Romans 14:5-6). However, for theological reasons, the church has always celebrated on the first day of the week–the day Jesus rose from the dead (see 1 Cor. 16.2; Rev. 1:10). This day (Sunday) came to be called the Lord’s day.
—Ben Witherington III