Matthew 12:40 For as Jonah was in the belly of the whale three days and three nights, so will the son of man be in the heart of the earth three days and three nights.
Some people have postulated that according to some Jewish custom any portion of a day or a night qualified as a day or a night. Somehow this convoluted numbering of days leads people to believe Jesus was buried on Friday evening and rose Sunday morning. Others have theorized that the events of the crucifixion week counted symbolically as being in the heart of the earth.
However, the following is a more likely timetable of Jesus being in the heart of the earth three days and three nights.
Jesus is buried on Wednesday evening (night 1)
Thursday (day 1)
Thursday night (night 2)
Friday (day 2)
Friday night (night 3)
Saturday (day 3)
Jesus is raised from the grave sometime around sunset on Saturday having been three full days and nights in the heart of the earth.
Here are all the verses which say "first day of the week" translated properly in regards to Jesus' resurrection.
Matthew 28:1 And late on Sabbath, in the evening on day one of Sabbath, came Mary the Magdalene, and the other Mary, to view the tomb.
Mark 16:2 And exceedingly in the morning of day one of the Sabbaths, they come unto the tomb, at the rising of the sun.
Mark 16:9 And having risen in the morning on the first day of the Sabbath, he appeared first to Mary the Magdalene, from whom he had cast out seven demons.
Luke 24:1 And day one of the Sabbaths, at deep dawn, they came unto the tomb, bringing aromatics which they prepared, and some others with them.
John 20:1 But on day one of the Sabbaths, Mary the Magdalene comes in the morning, still being dark, unto the sepulchre; and she sees the stone having been lifted from the sepulchre.
John 20:19 It being then late in that day, in the day one of the Sabbaths, and the doors being locked where the disciples were being gathered together because of the fear of the Jews, Jesus came and stood in the midst, and says to them, Peace to you.
Acts 20:7 And on day one of the Sabbaths, the disciples having been gathered to break bread, Paul reasoned with them, being about to exit the next day; and he extended the word until midnight.
1 Corinthians 16:2 According to one of the Sabbaths each of you by yourself put in! treasuring up what ever way he should be prospered in; that not whenever I come, then the collections should take place.
Note that in the above verses when the Greek word σάββατον (G4521) is translated as Sabbaths in the plural the Greek text also has σαββατων which is also plural. Using the plural form of Sabbaths indicates that it should not be translated as a singular week as many translations have done but as Sabbaths. Translating the word as week destroys the references to the Hebrew calendar, sabbaths, and feast days. The phrase "day one of the Sabbaths" was used to specifically refer to an interval on the Hebrew calendar when there was more than one Sabbath.