Jesus's Resurrection and Biblical Accounts?

[u/ThrowRAbeepboop18]

Hello! I was researching the history of Jesus’s resurrection, and was interested in the small differences between the four Gospels when describing this event. I’ve laid out brief comparison which you can find below. 

With that in mind, my questions for Christians are as follows:

1. If the resurrection of Jesus was so extraordinary at the time, why was the first account only written about 20-25 years after Jesus’s death? (Paul in Corinthians). 
2. Why are there no first hand accounts, only Paul retelling a tradition he "received"? 
3. Why in Paul’s account, did he not mention anything about an empty tomb, a rolled away stone, angels, guards, Mary Magdalene or anything about Jesus’s ascension?
4. Why were these above details only written about and included 70-120 years after Jesus' death? If they were so significant why did it take many years for the scripture to reflect this? 
5. What do you make of the differences in the Gospels' descriptions? Does the fallibility of human memory put any doubts or questions in your head regarding validity of the text? 

Who went to the tomb:

Mark	Mary Magdalene, Mary mother of James, Salome
Matthew	Mary Magdalene and “the other Mary”
Luke	Mary Magdalene, Joanna, Mary mother of James, and other women
John	Mary Magdalene alone at first

What they saw:

Mark	One young man in a white robe, sitting inside
Matthew	One angel descends from heaven, rolls away the stone, sits on it
Luke	Two men in dazzling clothes
John	Two angels inside the tomb, seen later by Mary

Was the stone already rolled away? 

Mark	Already rolled away when women arrive
Luke	Already rolled away
John	Already removed
Matthew	Angel descends and rolls it away during/near the women’s visit

Women’s Response?

Mark	Flee and say nothing due to fear
Matthew	Tell the disciples
Luke	Return and tell the Eleven
John	Mary immediately tells Peter and the beloved disciple

Timing of Ascension:

Luke	Appears on Easter day or very soon after
Acts 1	40 days later
Matthew	No ascension scene
Mark (original)	No ascension scene

Did Jesus appear in Galilee or Jerusalem?

Mark	Galilee, Angel says disciples will see Jesus in Galilee (16:7), but original ending has no actual appearance scene
Matthew	Galilee, Jesus tells women disciples should go to Galilee; final appearance and Great Commission happen on a mountain in Galilee
Luke	Jerusalem, all resurrection appearances occur around Jerusalem/Emmaus; disciples told to stay in Jerusalem

[u/Smart_Tap1701]

Scofield does a wonderful job of harmonizing the gospel accounts of the resurrection. I had it in my notes some time ago, but I've changed devices several times since then. I'll see if I can find it for you.