<P> Sabbatarianism arose and spread among both the continental and English Protestants during the 17th and 18th centuries . The Puritans of England and Scotland brought a new rigorism into the observance of the Christian Lord's Day, in reaction to the customary Sunday observance of the time, which they regarded as lax . They appealed to Sabbath ordinances with the idea that only the Bible can bind men's consciences in whether or how they will take a break from work, or to impose an obligation to meet at a particular time . Their influential reasoning spread to other denominations also, and it is primarily through their influence that "Sabbath" has become the colloquial equivalent of "Lord's Day" or "Sunday". Sunday Sabbatarianism is enshrined in its most mature expression, the Westminster Confession of Faith (1646), in the Calvinist theological tradition . Chapter 21, Of Religious Worship, and the Sabbath Day, sections 7 - 8 read: </P> <P> 7 . As it is the law of nature, that, in general, a due proportion of time be set apart for the worship of God; so, in his Word, by a positive, moral, and perpetual commandment binding all men in all ages, he hath particularly appointed one day in seven, for a Sabbath, to be kept holy unto him: which, from the beginning of the world to the resurrection of Christ, was the last day of the week; and, from the resurrection of Christ, was changed into the first day of the week, which, in Scripture, is called the Lord's day, and is to be continued to the end of the world, as the Christian Sabbath . 8 . This Sabbath is then kept holy unto the Lord, when men, after a due preparing of their hearts, and ordering of their common affairs beforehand, do not only observe a holy rest, all the day, from their own works, words, and thoughts about their worldly employments and recreations, but also are taken up, the whole time, in the public and private exercises of his worship, and in the duties of necessity and mercy . </P> <P> The confession holds that not only is work forbidden in Sunday, but also "works, words, and thoughts" about "worldly employments and recreations ." Instead, the whole day should be taken up with "public and private exercises of (one's) worship, and in the duties of necessity and mercy ." </P> <P> Strict Sunday Sabbatarianism is sometimes called "Puritan Sabbath", which may be contrasted with "Continental Sabbath". The latter follows the reformed confessions of faith of Continental Europe such as the Heidelberg Catechism, which emphasize rest and worship on the Lord's Day, but do not explicitly forbid recreational activities . However, in practice, many continental Reformed Christians also abstain from recreation on the Sabbath, following the admonition by the Heidelberg Catechism's author Zacharaias Ursinus that "To keep holy the Sabbath, is not to spend the day in slothfulness and idleness". </P>

When was worship changed from saturday to sunday