Are Christians really required to observe the 7th day or else they take the mark of the beast as some SDA claim?
Hello, I'm not SDA.
If you look at Colossians 2:16 by itself, then it is ambiguous as to when Paul was saying not to let anyone judge them for keeping God's holy days or for not keeping them, but it we look at the context of the views of the people judging them and keep in mind the theme that we must obey God rather than man, then it becomes clear:
Colossians 2:8 See to it that no one takes you captive by philosophy and empty deceit, according to human tradition, according to the elemental spirits of the world, and not according to Christ.
Paul would never have described those who were teaching obedience to the holy, righteous, and good commands of God in accordance with the example that Christ set for his followers as taking people captive by philosophy and empty deceit according to human tradition and not according to Christ. He went into more details about what these elemental spirits of the world are later in the chapter:
Colossians 2:20-23 If with Christ you died to the elemental spirits of the world, why, as if you were still alive in the world, do you submit to regulations— 21 “Do not handle, Do not taste, Do not touch” 22 (referring to things that all perish as they are used)—according to human precepts and teachings? 23 These have indeed an appearance of wisdom in promoting self-made religion and asceticism and severity to the body, but they are of no value in stopping the indulgence of the flesh.
So the Colossians were keeping God's holy days in obedience to His commands and in accordance with the example Christ set for us to follow, they were being judged by those teaching human traditions and precepts, self-made religion, asceticism, and severity to the body, and Paul was writing to encourage them not to let any man judge them keep them from obeying God.
Paul addressed these verses to those who formerly did not know God, aka former pagans. As such, they were formerly keeping God's holy day and therefore Paul could not have been criticizing them for returning to them. Furthermore, Paul would never have referred to the holy, righteous, and good commands of God as being weak and worthless elementary principles of the world. So whatever was being referred to in verse 10 is in the context of returning to paganism, not in regard to God's holy days.
Furthermore, Paul would not have referred to as obeying God's Law as being bondage. God did not save the Israelites out of bondage in Egypt in order to put them under bondage to His Law, but rather it is for freedom that God sets us free (Galatians 5:1) and God's Law is a law of freedom (Psalms 119:45), while it is sin in transgression of God's Law that puts us in bondage (John 8:34).
The opinion that we have of the Law matches the opinion that we have of the Lawgiver. For example, if someone thinks that God's Law is holy, righteous, and good, then they must also think that God is holy, righteous, and good for giving it. So if someone has such a low opinion of the Law that they consider it to be bondage, then they must also have an equally low opinion of God. The Psalms contain extremely high praise for God's Law, which certainly matched David's opinion of the Lawgiver, and if you consider the Psalms to be Scripture and to therefore express a correct view of God's Law, then you should share it instead of holding the polar opposite of the view expressed in Scripture.
So would these prove that Sabbath can be anyday? Also sabbath is a day of rest, you cannot work or go buying things, start a fire.
If God had wanted us to rest once per week, then He could have commanded that, but He only blessed the 7th day and commanded it to be observed.
Why would we be under the law again.
The existence of sin requires there to be a standard of what is and is not sin, and that standard is revealed through God's Law. Gentiles are either under God's Law and are obligated to refrain from sin and are not under God's Law, have no obligation to refrain from sin, and have never needed Jesus to give himself to redeem them from all Lawlessness.
However, God is God, so all Gentiles are under God's Law and are obligated to obey it and to refrain from sin regardless of whether or not they are in a covenant relationship with Him. For example, God judged the world the the Flood for their sins, God will judge the world in Revelation, God threatened to judge Nineveh, and God judged Sodom and Gomorrah for their Lawless deeds (2 Peter 2:6-8). So they didn't get a choice of whether or not they wanted to be under God's Law and neither do you. God have revealed to you what sin is through His Law and the choice that you do get to make is whether or not you are going to repent and obey by faith.
Is it a sin not to observe the 7th day Sabbath? It just doesn't seem so from the Bible. Old Covenant is different from New, if you pick and choose from old covenant why not follow the whole law then?
Indeed, it is always a sin to disobey God's Law (1 John 3:4). While we are under the New Covenant and not the Mosaic Covenant, we are nevertheless still under the same God with the same ways and therefore the same instructions for how to walk in His ways. For example, if the way to act in accordance with God's righteousness changed when the New Covenant was made, then God's righteousness would not be eternal, but God's righteousness and all of His righteous laws are eternal (Psalms 119:142, 160). So while the Mosaic Covenant has become obsolete, its instructions for how to train in righteousness did not become obsolete along with it, but rather all Scripture is still profitable for teaching, for reproof, for correction, and for training in righteousness, that the man of God may be complete, equipped for every good work (2 Timothy 3:16-17).
