Three things were accomplished on the cross
First, Jesus being perfectly innocent of any sin or crime and being executed resulted in His glorification: which simply means, God multiplied Jesus’ personal spirit after he died.
Jesus’ personal spirit was the spirit God chose to send to earth. It was a particular spirit’s turn to be born as a human being, just like all other human beings.
Jesus’ personal spirit is the spirit that left his body on the cross the moment he died. Physical death is caused by God’s Spirit leaving your human body, which also causes your personal spirit to leave your body.
Second, Jesus is the final sacrifice. Jesus’ blood being spilled on the cross made him the final sacrifice for all Mankind’s sins. It includes every person ever born on earth, but it doesn’t include anyone who freely chooses to reject God’s offer of being saved.
Jesus, having been a perfectly sinless human being, made himself the victim that became the offering, which paid for every sin ever committed by the human race.
There is only one exception to this accomplishment. The exception is one sin, known as blasphemy of the Holy Spirit, which is purposely contradicting and denying what is written in the Bible. It is not covered by this salvation plan.
Third, Jesus had successfully broken the curse on Mankind since the days of Adam. The devil was well aware of Jesus’ birth, existence, and mission.
This is why satan influenced King Herod to kill Jesus as a baby but his plot failed, which is a vital part of God’s protection plan, known as salvation, which is extended to anyone who truly chooses to believe God.
Jesus was satan’s only enemy, and that left satan no other alternative but to have Jesus killed. The devil believed that Jesus would have defeated him by getting all people to worship God, if Jesus were allowed to live.
Killing Jesus was satan’s greatest error, because sacrificing Jesus was the essence of God’s plan to defeat satan.
You could say satan defeated himself. When he influenced the brains of the Pharisees and Romans to kill Jesus, satan walked right into God’s trap.
Jesus had challenged satan during his lifetime and defeated him in death. Jesus challenged satan to a duel. The weapon chosen was the Bible.
Forty days after God anointed Jesus at John’s baptism; satan tried tempting Jesus by injecting thoughts into his brain.
Each thought from satan was defeated instantly by Jesus using the Word of God (the Bible) to prove his thoughts misinterpretations of Biblical principles, which makes them lies.
Thus, Jesus taught us how to counteract the ideas satan and demons put into the brains of people.