Is it wrong to tell christians they must observe the Sabbath?

Col 2: "Therefore let no man judge you in eating and drinking or in respect of a festival or of an observance of the new moon or of a sabbath." (If a person was under the Mosaic Law and was judged guilty of profaning the Sabbath, he was to be stoned to death by the whole congregation, according to Exodus 31:14 and Numbers 15:32-35.