Where in the New Covenant (NT) is the command to keep the sabbath?
The disciples were Jews who grew up keeping the Sabbath, so they did not need to be taught to keep it and there was never a time when their week was not based around keeping the Sabbath. We shouldn't even need anything to be repeated in order for us to know that we should still obey God.
Jesus was sinless, so he lived in perfect obedience to the Mosaic Law, which means that he would have still taught full obedience to it by example even if he had said nothing, including keeping the Sabbath throughout his ministry, and as his followers we are told to follow his example (1 Peter 2:21-22), to walk in the same way he walked (1 John 2:3-6), and to be imitators of him (1 Corinthians 11:1). Furthermore, Jesus began his ministry with the Gospel message to repent from our sins for the Kingdom of God is at hand (Matthew 4:17, 23) and the Mosaic Law was how his audience knew what sin is, so repenting from our disobedience to it is an integral part of the Gospel message, including repenting from breaking the Sabbath. In addition, Jesus also taught how to keep the Sabbath through his interactions with the Pharisees on the topic, such as in Matthew 12:1-13.
In Acts 15:21, the expectation was that Gentiles would continue to learn about how to obey Moses by hearing him taught every Sabbath in the synagogues. In Colossians 2:16, they were keeping God's holy days in obedience to God's commands in accordance with what Christ taught by word and by example, they were being judged by those teaching human precepts and traditions, self-made religion, asceticism, and severity to the body (Colossians 2:20-23) and Paul was writing to encourage them not to let any man judge them and keep them from obeying God. In 1 Peter 1:13-16, we are told to have a holy conduct for God is holy, which is a quote from Leviticus where God was giving instructions for how to have a holy conduct, which straightforwardly includes keeping God's Sabbaths holy (Leviticus 19:2-3).
The Sabbath is a precious gift from God give to His people for our own good in order to bless us, so even if we weren't commanded to keep it, then we should seek out the privilege and the delight of getting to keep it.
I'm not fooled quite that easily.
It was klutedavid who was saying that legalism has nothing to do with tradition and I was quoting him to disagree with him, but my quote tags were off.