One of the concepts that I've struggled with for some time is understanding mortality. At least in terms of omnipotence why would God be concerned with mortality? In fact, why would God care if we sacrifice anything, including His son if He could just on a whim bring him back to life, indeed, if Christ had the ability to bring people back from the dead, why would his mortality be of any consequence?
When we as humans play god as scientists in laboratories death is almost just as inconsequential. Death loses it's meaning if life prevails so readily that is hardly detrimental to kill and simply induce more life. I don't think there is a lot of scientists weeping when lab rats are exterminated and dissected in the name of experimentation. And we are as powerful as lab rats when it comes to facing God.
But God didn't make the us to be mortal. He made the world perfect, and it was only us as we gave into temptation and became separated from Him that death entered our world. The corruption from sin that saturates our physical bodies is so great we are born into it and death is one of the consequences of that.
So why the need for sacrifice?
From what I can see the sacrifice that started in the garden of Eden for the temporary covering of sin is a form of repentance. It is humbling for us to give up something that we value and animals were effectively a form of currency, so it is an offering to God to basically say we're sorry for what we've done.
God had another plan though, He sent us His son to cover us permanently for sin. He showed us his absolute love by humbling Himself down to the level we'd dug ourselves into. He separated part of Himself so that Christ could die and he could be our salvation. And when Christ was resurrected he didn't just stand up and walk away, like those that Christ himself brought back to life, but he returned to us gloriously to demonstrate that death, and therefore all the sin and corruption in the world could be defeated. Believing in Christ as our saviour is a belief that we can defeat the corruption and temptations of the devil. It is a fundamental message of hope that good can defeat evil and it shows us in terms that we can understand the grace that God has for us.