The Sabbath Day and the Lord's Day are two different things. The Sabbath Day (Saturday) was for those under the old testament. The Lord's Day (Sunday) is for those under the new testament. The Sabbath was to celebrate a finished creation. The Lord's Day is to celebrate a finished redemption. The Lord rose from the dead on a Sunday morning- making us all free. On Sunday we are commanded to give as we've been prospered, take the Lord's Supper, listen to a reading from God's holy word, and praise Him in song. Hmm, sounds like church service to me. Although the new testament speaks of a Sabbath rest with God in heaven forever, we are not under the physical laws of Moses- including the keeping of the Sabbath day on Saturdays. (Romans 7:1-4, Matthew 28:18).
The Sabbath, celebrates t finished creation, and the Lord day celebrates the finished redemption