Which day of the week does the Bible enjoin to be kept Holy?

Out of all of the Ten Commandments, the keeping of the Sabbath is the only one not mentioned in the NT; therefore (and also due to Jesus Christ really being our Sabbath), Christians are not "commanded" to keep any particular day as their Sabbath; some observe Sunday, while others believe that Saturday is "correct".........I enjoy the teachings of Pastor Chuck Smith, who says that every day is the Sabbath ;]