Shorter Catechism
Q 59. Which day of the seven hath God appointed to be the weekly sabbath?
A. From the beginning of the world to the resurrection of Christ, God appointed the seventh day of the week to be the weekly Sabbath;1 and the first day of the week ever since, to continue to the end of the world, which is the Christian Sabbath.2
Genesis 2:2-3
And on the seventh day God finished his work that he had done, and he rested on the seventh day from all his work that he had done. So God blessed the seventh day and made it holy, because on it God rested from all his work that he had done in creation.
Exodus 20:11
For in six days the Lord made heaven and earth, the sea, and all that is in them, and rested on the seventh day. Therefore the Lord blessed the Sabbath day and made it holy. (ESV)
Mark 2:27-28
And he said to them, “The Sabbath was made for man, not man for the Sabbath. So the Son of Man is lord even of the Sabbath.”
Acts 20:7
On the first day of the week, when we were gathered together to break bread, Paul talked with them, intending to depart on the next day, and he prolonged his speech until midnight.
1 Corinthians 16:2
On the first day of every week, each of you is to put something aside and store it up, as he may prosper, so that there will be no collecting when I come.
Revelation 1:10
I was in the Spirit on the Lord’s day, and I heard behind me a loud voice like a trumpet (ESV)