Some Sabbatarian Christians say that Isaiah 66:23 proves that the Sabbath will be kept in the New Earth and therefore we should be keeping it now. But is this so? Please consider this passage in Isaiah.

Do most Sabbatarian Christians keep the new moon days? Why is this often considered ceremonial and the Sabbath mentioned in this text not? Isaiah wrote this in the last half of the 8th century B.C. Isaiah lived during the period of the Old Covenant. A probable explanation is that the prophet was expressing what the Lord revealed to him about the New Earth the best way he could. Perhaps Isaiah, being a devout Jew, saw as part of the joy of living in the New Earth all nations celebrating the Sabbath and new moon days, but it also could be he could not imagine any time in the future when these days would not be celebrated. This appears to be another example of an anachronism. For in chapter 56 he speaks of Sabbath-keeping, but this along with the practice of making "burnt offerings" and "sacrifices" on God's altar (Isaiah 56:7). Will this practice continue in the New Earth? Will the Levitical priesthood continue to be in existence in the New Earth (Isaiah 66:21)? This does not seem likely.

Biblical writers, while they were inspired by God to write what they did, wrote within their cultural perspective. To illustrate this point, in Genesis 1 days are defined as being evenings and mornings. Part of the custom of the ancient Israelites during the time of Moses was to reckon days in this fashion. And this custom was shared by the ancient Phoenicians, Athenians, Arabs, Germans, and Gauls. But this way of reckoning time was not the only one used in the ancient world. For example, the Romans defined days as being from midnight to midnight, which is the reckoning most of the world uses today. If God had revealed the creation story to one living within ancient Roman culture, that person would probably have said in Genesis 1:5, "And midnight came, one day." Isaiah, like Moses who wrote Genesis centuries earlier, was influenced by the culture and customs of his day when he wrote under the inspiration of the Holy Spirit. So while truths are expressed in this prophecy, it should be kept in mind that they were expressed within this context.

Because of this, it is quite possible that Isaiah could have used the terms sabbath and new moon as a means by which to measure time, since these terms were an integral part of his cultural heritage as an ancient Israelite. If Isaiah were alive today, he might have just as easily said, "And it will be from month to month and week to week ..." God probably revealed this prophecy in terms Isaiah and those he spoke to could understand. In Old Covenant terms, since Christ had not come yet. So this passage of Scripture cannot reasonably be used to justify mandatory Sabbath observance.