That is his punishment to rule earth and now God has to die to take away his authority
and what differences does this mark. Satan already has authority over man once again on earth, if we assume God death on the Cross would remove his authority, then he failed because satan still rules earth.
Your misunderstanding Jesus's death on the cross and salvation, but I'm falling asleep while writing so i cant really make a solid explanatory post atm.
Satan didn't know Jesus's nature. All Satan knew was what the Jews knew - i.e. what was written in scripture which wasn't necessarily explicit. Prophecy never is.
God did cast Satan out of heaven, and yes Satan has power in this world... that doesn't affect as much as you might think.
We people are a depraved lot. And honestly, we don't much need Satan to conceive of the most evil of things. Our father, as the Bible says, is who our nature displays.
If our nature is displaying a sin nature we are "of our father the devil"
If our nature is displaying a Godly nature, we are children of the living God.
We are born with a sin nature, we don't need much help with desiring sin.
But Jesus overcame sin, and through Jesus, Satan is bound for the believers. Beyond that, it's just who we are, and often we fight our own dual nature..
But Jesus died, because sin came into the world through one man, and so through one came our salvation.
Most of how God deals with His people though, is because that is how we asked HIM to... got bored with manna everyday, wanted spices instead..... decided we wanted a king like other nations...etc etc etc.
1 Samuel 8:7
And the Lord told him: Listen to all that the people are saying to you; it is not you they have rejected; but they have rejected me as their king