But if he rose from the dead when three days were accomplished he would be raised on the 8th...
Wrong.
Today - 5th
Tomorrow - 6th
Third day - 7th
In the BIble, the third day is the day after tomorrow. Tomorrow is always the day after today.
Please look up how Jesus counted days in Luke 13.
That is why there is absolutely no doubt, none, that we can say with 100% certainty that Jesus died on the sixth day ( Friday ) and rose on the third day ( Sunday )