Let’s discuss the church’s horrific misunderstandings about God’s commanded Seventh Day Sabbath, as there are so many misconceptions. Here’s just one example of someone trying to justify "Sunday" Sabbath:
“It is well documented that the early church adopted Sunday as their day of worship. Acts 20:7 speaks of this, "On the first day of the week we came together to break bread. Paul spoke to the people …" and 1 Corinthians 16:2, "On the first day of every week, each one of you should set aside a sum of money in keeping with his income, saving it up, so that when I come no collections will have to be made." These passages indicate that Christians were probably meeting regularly on Sunday (the first day of the week).” (Source: Got Questions.org)
WHY IS THAT STATEMENT WRONG? Let’s view this using a Hebrew, as opposed to Greek understanding.
Referencing Acts 20:7:
Fact is, Jewish believers in Yeshua continued meeting at synagogue (or the Temple) for Sabbath. Common practice would be havdallah - meeting in homes after sundown on Saturday to continue discussions and praise from the Sabbath, which explains Paul "preaching until midnight" in Acts 20:7. The first day of the week for Jews (like Paul) began at sundown at the end of the Sabbath - Saturday evening - not "Sunday."
Referencing 1 Corinthians 16:2:
Acts records 84 occasions when he met in the synagogues on Shabbat. Paul does not want his hosts to break the Shabbat and he counsels them to make ready for him in advance. All early Netzarim believers like Paul rested on the Seventh Day Shabbat in Mashiyach.
Paul asks people to make preparations on “the first day” (i.e. work), which PROVES that neither he nor the Corinthians viewed the first day of the week as a Shabbat. Paul's actions speak volumes FOR the Seventh Day Shabbat!
Furthermore, and most importantly, neither the Father nor the Son has ever claimed the first day as His own in any higher sense than He has each or any of the other laboring days. Neither of them has ever placed any blessing upon it, or attached any sanctity to it.
The Bible tells us God expressly reserved the seventh day to Himself, placing His blessing upon it, and claimed it as His holy day. (Genesis 2:1-3.) Moses told Israel in the wilderness of Sin of the sixth day of the week, "Tomorrow is the rest of the holy Sabbath unto the Lord." Exodus 16:23.