Remember that according to Ephesians 2:12-16 the Gentiles were once excluded from the commonwealth of Israel and were strangers to the covenants of promise. But now Messiah has reconciled them both in one body to God through the cross, so that now we too are fellow citizens of Israel. Judgment deferred is not judgment denied. We truly have been walking in his grace, but the time has come for His people to start walking according to His instructions. Matthew 7:21-27 stresses that the wise both hear and do His Word. Remember that the foolish virgins mentioned in Matthew 25 were all expecting the Bridegroom, but only five were wise and were granted entry into the wedding feast.
The answer is found in the phrase “one person.” This passage is discussing days established by men. The Sabbath was instituted by the Master of heaven and earth at creation, and that which He establishes can not be changed by our opinions.
Matthew 24:20
(This passage would make no sense if any day of the week would qualify as the Sabbath. Furthermore, why would He even mention the Sabbath if He didn't expect His followers to be observing that day in the future?)
To properly understand this passage, we need to comprehend how the Hebrews kept time. In the beginning the FATHER established the following: "God called the light day, and the darkness He called night. And there was evening and there was morning, one day." Genesis 1:5 (NASB) Therefore, the Hebrew day begins at sunset. The believers mentioned above had concluded the seventh day Sabbath, and Paul continued to teach late into the night. This would explain why they had torches. In our culture we would call it Saturday night. This passage has nothing to do with Sunday worship.
"The Sabbath was binding in Eden, and it has been in force ever since. This fourth commandment begins with the word ‘remember', showing that the Sabbath already existed when God wrote the law on the tables of stone at Sinai. How can men claim that this one commandment has been done away with when they will admit that the other nine are still binding?"
- D.L. Moody, Weighed and Wanting, pp. 7, 48