Cordially,
Mat 12:8 For the Son of Man is Lord even of the Sabbath." ... Mar 2:28 Therefore the Son of Man is also Lord of the Sabbath." ... Luk 6:5 And He said to them, "The Son of Man is also Lord of the Sabbath."
Now when connected to these passages and knowing that Christ is currently High Priest, then what day should those under Christ show up for duty?
1Pe 2:9 But you are a chosen generation, a royal priesthood, a holy nation, His own special people, that you may proclaim the praises of Him who called you out of darkness into His marvelous light; 10 who once were not a people but are now the people of God, who had not obtained mercy but now have obtained mercy.
Peter does not tell us we are a church, he tells us we are chosen priests and a holy nation that is special to Him. (See Ex 19:5-9)