acctually God was made flesh "for he so loved the world that he gave his only begotten son" It's an act of mercy.
Adam & Eve were to live eternally -- God back then only made one rule and Adam & Eve broke it, that disobidiance had them thrown out of paradise and punished Adam & Eve with death.
Then God brought his Law... if you individually could uphold each and every law wich is revealed, you'd get salvation. Yet even the prophets and the most traditional of the rabbi's could not uphold all the laws and ritually had to pay blood atonement for remission of sin. When Abraham was about to kill Isaac, Abraham told "God will provide the burnt offering himself". and as Jesus said himself "Abraham rejoiced to see my day".
So what do we have:
- continuety of mortal decay and a law no man can uphold
what causes mortal decay? the law we cannot uphold
So imagine someone could uphold the law? It must be impossible for any man to resist every temptation. Yet it has to be a man, because the law is made for men. So in God's grace he sent Jesus as a represantive of Him. Jesus sinlessness acctually entitled him to live forever just like Adam & Eve... yet he didn't, he dodged the bullet for us, took upon him all sin in the world and died for us.
And as a ransom if we wanna live eternally too, then we must do the deeds and say the words Jesus would have when he should of been alive in our place. He is our mediator, trough Him we go to God.