We all should know by now that Jesus was crucified on Wednesday. And, three days later He arose.
Thursday was an High Holy Sabbath: The Jews therefore, because it was the preparation, that the bodies should not remain upon the cross on the sabbath day, (for that sabbath day was an high day,)
John 19:31 (KJV)
WED 6PM to THU 6PM = 1 day
THU 6PM to FRI 6PM = day 2
FRI 6PM to SAT 6PM = 3 days Jesus arose sometime after on the first day of the week which began at 6PM SAT.
High Holy Sabbath is a regular happening event ever so often. Saturday is not the only Sabbath day.
Some try to say Jesus was place in the tomb on Friday. That would only make one day in the tomb.
Regarding Easter: it is pagan from Babylonian worship. Jews observe Passover and Christians observe Jesus' resurrection.
Now about that time Herod the king stretched forth his hands to vex certain of the church. 2 And he killed James the brother of John with the sword. 3 And because he saw it pleased the Jews, he proceeded further to take Peter also. (Then were the days of unleavened bread.) 4 And when he had apprehended him, he put him in prison, and delivered him to four quaternions of soldiers to keep him; intending after Easter to bring him forth to the people.
Acts 12:1-4 (KJV)
Herod was observing the pagan Easter. Neither Christians nor Jews observed Easter.