Some calendars now have Monday as the first day of the week. How does that affect Christians? Are we supposed to worship on Monday now? Is Sunday the seventh day now?
Christians worship on the first day of the week (which is Sunday) because that is the day specified and authorized by God. The Jews were to “remember the Sabbath” (Ex. 20:8), which is “the seventh day,” i.e., Saturday (Ex. 16:26). Jesus was crucified on “the Preparation Day, that is, the day before the Sabbath” (Mark 15:42). Then, on “the third day” (Luke 24:7, 21, 46), which is “the first day of the week” or Sunday (24:1), “He rose again” (1 Cor. 15:4). That is the day that the New Testament church gathered to worship (Acts 20:7; 1 Cor. 16:2), and thus, it is the day that the New Testament church is to gather to worship today and till the end of time.
The seventh day and the first day of the week have always been the same. Today we call them Saturday and Sunday. God’s will has not changed (and will not) regarding worship on Sunday!