The vast majority of Christian churches today observe Sunday, the first day of the week, as a time for rest and worship. History reveals that it was decades after the death of the apostles that a politico-religious system substituted the observance of the first day of the week for the seventh day. Roman Catholic sources acknowledge that there is no Biblical authority for the observance of Sunday, asserting that it was the Roman Church that changed the day of worship from Saturday to Sunday. They claim that the Church, by virtue of a divine mission, transferred the solemnity from Saturday to Sunday, choosing it as a day of worship. Protestant theologians and preachers from various denominations also admit that there is no Biblical authority for observing Sunday as a day of worship, noting that the reason for keeping the first day holy stems from church tradition rather than Scripture.

In the Christian era, the majority of professing Christians hold the first day of the week as the proper day of worship. Catholic theologians openly admit that their church made this change, asserting their authority to modify such matters. Protestants, however, justify Sunday worship as a tradition honoring the day on which Christ rose from the dead. Yet, there is no biblical record or hint of God transferring the sanctification and holiness from the seventh day to another. The assertion that the Sabbath has changed implies that the Creator Himself is changeable, contradicting the truth that with God there is no variation or shadow of turning, as James 1:17 affirms, and that Jesus Christ is the same yesterday, today, and forever, as stated in Hebrews 13:8. Thus, any claim of a change in the day of worship stands as an affront to His perfect, constant nature.

Protestant theologians justify their breaking of the fourth commandment and their worship on the first day of the week by claiming to honor the day of Christ's resurrection, despite no indication that God intended such a change. There is no explanation from any apostle, prophet, or messenger to support this doctrinal deviation. The timing of His resurrection, while critical to proving He is the Messiah, has nothing to do with establishing which day God set apart and made holy. The same theologians who justify Sunday observance also claim that He died on a Friday afternoon and was resurrected on a Sunday morning, which does not align with the three days and three nights He foretold. Sunday-keeping remains a tradition of men rather than an ordinance of God. Jesus' resurrection made no change in the day of worship; men took it upon themselves to alter it without respect to God's Word.

Protestants, since their emergence in the sixteenth century, have uniformly observed Sunday as the day of worship, aligning with a practice that spans over 300 years. This widespread custom among the Christian world stands in contrast to the Seventh-day Adventists and Israelites, who adhere to Saturday for the worship of God. The fervor for Sunday observance is evident in the impassioned protests from Protestant pulpits against Sabbath violation, notably seen in the widespread outcry and petitions against opening the World's Fair on Sunday. Such actions reflect a deep commitment to preserving the sanctity of the first day of the week among the majority of Protestants.

Professing Christians celebrate Easter as a day of worship on Sunday, believing that Jesus instituted a new day of worship when He rose from the grave on the first Easter Sunday morning. This belief leads them to disregard God's command to keep the seventh-day Sabbath. However, Scripture does not support a Sunday resurrection. Mary Magdalene arrives at the grave early on the first day of the week while it is still dark and finds that Jesus has already been resurrected. Even if one assumed Christ rose at dawn on Sunday, counting back 72 hours brings one to dawn on Thursday, and God's Word explicitly states that Christ was buried at sunset. Jesus rose on the day of which He declares Himself Lord: the true seventh-day Sabbath.

Many Christians hold the assumption that Sunday is the approved day for worship. However, the Roman Catholic Church asserts that it transferred Christian worship from the biblical Sabbath, which is Saturday, to Sunday. The Church argues that attempting to claim this change is supported by the Bible is dishonest and denies Catholic authority. Over one hundred years ago, the Catholic Mirror published articles emphasizing that unless one accepts the authority of the Catholic Church to designate the day of worship, Christians should observe Saturday. These articles point out a direct contradiction between the teaching and practice of Protestant Christianity, with the exception of Seventh-day Adventists, and that of the Jewish people, both observing different days for the worship of God. The Bible, as the sole teacher for Protestants, does not indicate any change from Saturday to Sunday as the day to be kept holy, despite the widespread practice of Sunday worship among many Christians since the Reformation.

The first reference to Sunday after the resurrection of Christ, as found in St. Luke's Gospel and St. John's Gospel, shows the apostles gathered on the day of the resurrection, Easter Sunday. This meeting was not for inaugurating a new departure from the old Sabbath, Saturday, as there is no hint of prayer, exhortation, or reading of the Scriptures. Instead, it reveals their demoralization, huddled together in fear of the Jews. The second instance, also in St. John's Gospel, occurs eight days later on a Sunday, when the resurrected Redeemer met with all the apostles to address Thomas's incredulity. Even on this occasion, not a word is mentioned of prayer, praise, or reading of the Scriptures, missing an opportunity to change the day of observance. The third instance, in Acts, refers to the apostles being together on the Feast of Pentecost, a Sunday. This day, however, offers no basis for substituting Sunday for Saturday, as the Jews had been observing this festival on Sunday for over 1500 years alongside the weekly Sabbath. Another reference in Acts mentions the disciples coming together on the first day of the week to break bread. Yet, this does not establish Sunday's exclusive prerogative, as another verse in the same chapter notes they broke bread daily, undermining any unique significance for Sunday. Finally, in I Corinthians, St. Paul instructs a collection for the saints to be taken on the first day of the week. This request does not override the established routine of reading Scriptures, prayer, exhortation, and preaching every Sabbath, Saturday, as had been consistently practiced. The collection on Sunday is akin to necessary tasks deferred from the Sabbath, similar to the postponement of embalming Christ's body until after the Sabbath had passed. Thus, no evidence supports the substitution of Sunday for Saturday as the day of observance.

The belief in the Good Friday-Easter Sunday timeline held by mainstream Christians is deeply tied to the practice of Sunday worship. If the argument that Jesus Christ was buried for a complete 72 hours—from Wednesday at sunset to the weekly Sabbath at sunset—is correct, a significant portion of mainstream Christian theology, particularly Sunday worship, would be undermined. Despite this, many cling to the traditional timeline, often ignoring the biblical evidence that supports a different chronology of events surrounding Christ's death and resurrection.

In our investigation, we propose to carefully examine the claim that God substituted Sunday for Saturday as His day of worship in the new law. We have critically analyzed texts in the New Testament under the title Sabbath, numbering sixty-one, and those referring to the first day of the week, or Sunday, numbering eight, finding no evidence of a change in God's will regarding His day of worship. We now turn to a third class of texts often cited to support this substitution, those mentioning the day of the Lord or the Lord's day, to determine if they provide any warrant for such a change. Examining these texts, we find in Acts 2:20 a reference to the day of the Lord as a time of great judgment, not Sunday. Similarly, in I Corinthians 1:8 and 5:5, the day of our Lord Jesus Christ clearly points to the day of judgment, not a weekly observance. Further texts in II Corinthians 1:13-14, Philippians 1:6 and 1:10, and II Peter 3:10 and 3:12 consistently indicate the day of the Lord as the final judgment, rendering any application to Sunday absurd. The final text in Revelation 1:10, where John states he was in the Spirit on the Lord's day, aligns with the same meaning of judgment day, as his vision pertains to future events in heaven, not a weekly day of worship. We have presented eight of the nine texts relied upon to equate the Lord's day with Sunday, and each unequivocally refers to the day of judgment. Even in Revelation, where Sunday had previously been called the first day of the week by John, there is no basis to assume a new designation for Sunday as the Lord's day. Thus, no scriptural support exists for the assertion that Sunday replaced Saturday as the day of worship ordained by God.