Shouldn’t Christians observe a Sabbath Day?

You are correct that the Sabbath Day was established in Genesis 2, when the Lord set it apart (i.e., consecrated it). The day was set apart from the other six days of the week not to establish a day of physical rest for men (that purpose wasn't associated with the day until thousands of years later during the giving of the Law to Israel), but rather the Lord set it apart for Himself to establish an important spiritual picture to teach about resting in Christ.

In reality, there are three Sabbaths mentioned in Scripture, and all are related in an important way. First, the Lord created a Sabbath for Himself in Genesis 2. The Lord did all the work and He earned a permanent, eternal rest His work of Creation. Secondly, there is the Sabbath established in Exodus 20 for Israel. Isreal worked six days a week, and then Israel enjoyed a single day of temporary rest under the Law of Moses. Finally, there is a Sabbath established in Christ is for all believers. Christ did all the work of salvation, and Christians enjoy a Sabbath from works of salvation when they trust in Christ alone. (The book of Hebrews teaches the relationship between these Sabbaths in chapter 4.)

Moreover, the Bible teaches that Christians are not subject to the Law of Moses, but this does not mean that we are under no law at all.  On the contrary, Christians are bound by a law that prohibits murder, stealing, coveting and countless other offenses, because Christians are bound to the much stricter law called the Law of Christ (or the law of Liberty, as James calls it). 

This law calls us to obey Jesus' commandments in every area of our life - both in action and in our heart's desires - and to remain holy in areas of our behavior and thoughts that the Old Covenant Law never even attempted to regulate (i.e., lusting).

If you are interested to learn more about how the Sabbath is fulfilled by our faith in Christ and about the law of Christ, our ministry has several articles and related Bible study teachings on the topics of the Sabbath and the Christian's relationship to the Law, and we encourage you to consult these resources to understand the Bible's teaching. In particular, we recommend the following articles:

Which day is the correct Sabbath day?

How should a Christian approach the Sabbath?

On Law and Liberty

Meanwhile, we also acknowledge that many churches and denominations still teach that Christians are bound to the Old Covenant Law and are obligated to observe a day of rest or Sabbath day. These teachings are based on traditions that run deep in our Christian culture (but are not grounded in a proper view of Scripture), so many Christians have come to accept this teaching without personally studying the counsel of Scripture on this important point.

Nevertheless, tradition is not to be the basis for our Christian understanding and living, since our church traditions (and even our church leaders) can be in error, which is why the Bible commands us to seek the Scriptures daily to know the truth through the teaching of the Holy Spirit.

While there is nothing wrong with choosing to observe a Sabbath Day (whether Saturday or Sunday) if you feel convicted to do so, just remember that your convictions may not be shared by other believers, and they have liberty in Christ to follow a different practice.

Verse By Verse Ministry is committed to teaching only the truth of Scripture even when it conflicts with church tradition.  Remember the words of Jesus in addressing the Pharisees, who were guilty of teaching religious traditions rather than God's word:

Matt. 15:3 And He answered and said to them, “Why do you yourselves transgress the commandment of God for the sake of your tradition?
Matt. 15:4 “For God said, ‘ HONOR YOUR FATHER AND MOTHER,’ and, ‘ HE WHO SPEAKS EVIL OF FATHER OR MOTHER IS TO  BE PUT TO DEATH.’
Matt. 15:5 “But you say, ‘Whoever says to his father or mother, “Whatever I have that would help you has been  given to God,”
Matt. 15:6 he is not to honor his father or his mother .’ And by this you invalidated the word of God for the sake of your tradition.
Matt. 15:7 “You hypocrites, rightly did Isaiah prophesy of you:
Matt. 15:8 ‘ THIS PEOPLE HONORS ME WITH THEIR LIPS,
BUT THEIR HEART IS FAR AWAY FROM ME.
Matt. 15:9 ‘BUT IN VAIN DO THEY WORSHIP ME,
TEACHING AS  DOCTRINES THE PRECEPTS OF MEN.’”
 

And again in Mark:

Mark 7:8 “Neglecting the commandment of God, you hold to the  tradition of men.”
Mark 7:9  He was also saying to them, “You are experts at setting aside the commandment of God in order to keep your tradition.