Acts 13:42 - And when the Jews were gone out of the synagogue, the Gentiles besought that these words might be preached to them the
next sabbath.
Acts 13:44 - And the next sabbath day came almost the whole city together to hear the word of God.
Acts 17:2 - And Paul, as his manner was, went in unto them, and three sabbath days reasoned with them out of the scriptures,
Acts 18:4 - And he reasoned in the synagogue every sabbath, and persuaded the Jews and the Greeks.
These were people that didn't know and/or want to believe that Jesus Christ WAS the Messiah, and I'm sure some of them had never heard the Word.
The Gentiles besought that the Word be preached to them on the next Sabbath. What a great opportunity for Paul to tell them that Christians would meet on Sunday...but he didn't.
Paul was at Corinth for a year and a half. Obviously since he "fathered" the church he would've impressed upon them that the Sabbath day was changed to Sunday in that amount of time...but he didn't.
Sabbath-keeping is an easy thing to explain. It is called a "holy convocation" which means an assembly. Going to church, worshipping the Creator, resting from secular work and dedicating an entire day to praying, learning, fellowshipping and resting. It's a wonderful delight and a blessing. I look forward to it every week.
Jesus said it was lawful to do good on the Sabbath day--we all know that He healed people, etc. Many Sabbath-keepers like to go to hospitals on the Sabbath and witness to those that are ill/hurting. Others go to retirement homes to spend time with the elderly. Spreading God's Word on His holy day and helping people in need of hope.
Reading scripture, refraining from buying or selling, fellowshipping with your church family.....ahhh, what a glorious day!
Remember the Sabbath day and keep it holy.
Psalms 40:8 - I delight to do thy will, O my God: yea, thy law is within my heart.
I'm going to post a study I did on Jesus vehemently fighting against the Pharisees about the Sabbath.