"Therefore do not let anyone judge you by what you eat or drink, or with regard to a religious festival, a New Moon celebration or a Sabbath day. These are a shadow of the things that were to come; the reality, however, is found in Christ."
Furthermore, I think we should be careful about taking just parts of the law and elevating them above the others, as written in James 2:10:
"For whoever keeps the whole law and yet stumbles at just one point is guilty of breaking all of it."
Which is why it's surprising that someone will say we must keep the sabbath, and yet ignore some of it's requirements such as the duty to put someone to death if they decide to do any work on that day:
"For six days, work is to be done, but the seventh day shall be your holy day, a Sabbath of rest to the LORD. Whoever does any work on it must be put to death." [Ex 35:2]
So if you insist on keeping the Sabbath you cannot just keep one part which says it's a day of rest and throw away the rest of the requirement. You will still have broken the Sabbath if you do not carry out all of it's rules and regulations. Nevertheless, because of Colossians 2:16 we see that the observance of a Sabbath day has been done away with along with the restrictions to eat certain foods that God once called unclean.
"Do not call anything impure that God has made clean." [Acts 10:15]
Are we then free of all law keeping and of obeying God's requirements in the Old Testament? Nope, but rather we fulfill them in Christ who is Lord of the Sabbath and desires us to offer our "bodies as living sacrifices, holy and pleasing to God—this is your spiritual act of worship."
But what did Christ say concerning this matter?
"Teacher, which is the greatest commandment in the Law?" Jesus replied: " 'Love the Lord your God with all your heart and with all your soul and with all your mind.'This is the first and greatest commandment. And the second is like it: 'Love your neighbor as yourself.'All the Law and the Prophets hang on these two commandments."