Christians do have a Sabbath, but it's not a day of the week. It's not Sunday...or Saturday.
The Sabbath Day practiced by Israel was a symbol, a message in pantomime. It pictured a rest from working for the salvation that the human race needed because of our sentencing to separation from God and punishment for our sins. We were born dead to God because we inherited the sin from our primal parents, Adam and Eve. We are one with them.
The Jews worked (and many Christians today still make this mistake) for Salvation by obeying the Law given by God through Moses. The Sabbath Day actually pictured and prophesied a rest from this ineffective way of salvation.
The Law of Moses was true and accurate. It was holy. Yet God made it to teach and convict. The Law was a message in pictures. It was a skit with an embedded message. The Law was about mankind's weakness and even mankind's inability to keep any law. It was also a message of the true way to be saved.
Only a few people began to realize that fact, people like King David. The only way to get rest from sin was to have a Savior who would take our place, fulfill the Law on our behalf, and bear our Sin as well as our sins. The Law of Moses actually preached about Jesus. King David and others put their trust in this coming Messiah in advance. Let's think about that for a moment.
The only way to get right with God is connection with Jesus--spiritual connection. The first step is to consider, by faith, ourselves dead to self and sin. If we will ourselves to be dead to sin the next step is, through faith and the supernatural work of the Holy Spirit, to ask Jesus to take our sins and then to make us alive. We are supernaturally united with the life, death, burial, resurrection, and Spirit of Jesus Christ. His righteousness is, by our faith in Christ's death and resurrection on our behalf, imputed to us.
According to Merriam-Webster's dictionary the word impute means: to credit or ascribe (something) to a person or a cause. You and I are still sinners by nature, but a book that God keeps in Heaven lists us as sinless.
One other thing happens when we are forgiven and united with Christ. We have entered the Sabbath Day--"the Day of Rest." So, the Sabbath Day in the Law of Moses was a picture of this fact. For this reason, we worship by keeping the Sabbath every moment of our life. Each morning we recommit our lives to Jesus to allow Him to live through us that day. Remember, the manna from Heaven was only good for that day. It spoiled if left over for the following day. Jesus is the Manna from Heaven. He is our spiritual food.
And, now, to the main point of this article: The "church" as we erroneously translate the original Greek, which means assembly--the assembly can meet any day, any time, any where--even under a tree or in a house. We are free to assemble together as the Body of Christ whenever. We just need to be faithful in doing it together with a group of other believers.
We assemble because we need the strength, encouragement, and wisdom that comes from one another. And we need to establish koinonia through prayer, Bible reading, and Bible study. We need the blessings of the spiritual gifts that others have and they need the blessing of our spiritual gifts. So let's keep the Sabbath every day, yet not forsake assembling together regularly. And do not forget private devotions, too!