The significance of Good Friday

For me, the significance of Good Friday is that this was when Jesus died; which he needed to do in order to fulfil, to complete, his core mission. 

He did not need to die in the way he did, because any mode of death would suffice; and death was inevitable one way or another, sooner or later, for Jesus as for all mortal Men...

But Jesus did need to die; in order to resurrect, and ascend to Heaven. 

I believe that Heaven as a state-of-being already existed before Jesus died, and that Lazarus was probably its first inhabitant - albeit Lazarus returned to dwell on earth, for a while. 

But in order for "everybody" who thenceforth desired resurrection and eternal life to be able to achieve these; Jesus himself needed to die, be resurrected, ascend. 

That salvation for "everybody" includes those who had died before the time of Jesus - and who resided as spirits in Sheol/ Hades, or had reincarnated, or were ghosts, or even demons who were not fully corrupted...

Which is what "the harrowing of Hell" on Easter Saturday, represents in a symbolic but distorted fashion.