That is a very illogical conclusion to make. You saying that it is FRIDAY simple BECAUSE BECAUSE BECAUSE with nothing on the other end of BECAUSE other than that is how they do it now - which a logical person would know that has nothing to do with how they did it then and surely yourself included.
Christ was crucified on preparation day, rested in the grave on the sabbath, and rose on the 1st day. Read that over again and tell me if the order sound signficant... because it is. There is pretty deep meaning to the order of these days occruing on the days they do that is echoed through out scripture.
Genesis creation shows us day 1 is the begining of the work where light is spoken into darkness that leads up to the 6th day when God is finished his work. This ushers in the 7th day rest, not because God is tired, but because his work is finished which is an important disctiction. God is finished his work therefore he ceases (sabbath) his work. In the same way Christ's work was finished on the cross, it was exactly what he uttered as he took his last breath "It is finished". This ushers in the day of rest because the work is finished. Perperation day in this case in perperation of the Lamb of God and declares the work of Christ complete ushering a day of rest from this completion.
The sabbath is about rest for you and any everyone you are responsible for, even the animals and slaves, This is a powerful metaphor because animals and salves have no authority to take rest and they can only rest when they are given rest by someone with authority, namely the master (this also works for the entire household but is clearest with animals/slaves). In the same way, we cannot actually take this rest ourselves because we have no authority to enter God's rest but instead we can be given rest by one with authority. That one is Christ, and that work he accomplished to give us rest was finished on the cross.
Christ can do this because he was there when the Sabbath was made, he also fulfills the demands of the Sabbath. The requirements of the sabbath may only go to what is physically appropriate but the demand and logic for rest on the sabbath goes to our beating hearts and our very breath we take as work. Christ rested fully on the sabbath as he was in the grave during its duration without breath and without a heartbeat. So it is Christ who truly keeps the sabbath more than anyone else. But the catch is Christ needs to be in the grave on the Sabbath.
Christ then rises on the 1st day an instant call back to the light spoken into the darkness from creation, a type of new creation, a new beginning. But unlike his birth which was light sent into the darkness his rising is his defeat over the darkness. This needs to be on the 1st day because it is a part of the typology that is repeated throughout scripture.
these aren't random days, they are there by design. Christ tells us man is not made for the sabbath but the sabbath for man and in the same breath Christ says he is Lord of the Sabbath. Being "Lord" of something means you have authority over it. So Christ has authority over the Sabbath. Being the "Son of Man" the Sabbath itself is made for him as the Son of Man since the sabbath is made for man. It is made from the beginning with foreknowledge that Christ would finished his work on the 6th day through the crucifixion when he declares "it is finished" and then rest in the grave on the 7th day. Then rise anew on the 1st day.
Perhaps the order of the days today are different than the order of the days in the 1st century, I really don't know and nothing you have provided here convinces me. But it really doesn't matter who is doing the counting. all measurement is arbitrary if it has no meaning so what matters is the meaning behind the order of the days not which order it may be. If the Jews counted differently than the Romans so be it but it is fundimental that Christ dies on the 6th day, rests on the 7th day and rises on the 1st day. The bible confirms this order and it is consistent with the typology preordained since the beginning. Western interpretation may call preparation day = friday, the sabbath = Saturday and the 1st day = Sunday, these names may be a misnomer these terms were not in practice in the 1st century but they can still be referenced correctly to establish when Christ died. However, saying Christ died on a Sunday by reconciling a different system with a controversial hypothetical system is not only meaningless it robs Christ of his victory on the cross.
