This post is inspired by anonymous comments made elsewhere on this blog. I am going to use the anonymous questions and statements in quotes as a foil for a presentation of questions and answers on the cross. I will use some comments directly, but others I will change slightly.
“You make much of the notion that Christ had to die for our sins because we did not follow God’s law. Conveniently, the one that makes the law decides if you broke it and determines the punishment.”
The law of God is not arbitrary, that God could choose to make the law be whatever He wanted it to be. Since God’s law is not arbitrary, this is not a valid objection.
God could no more make the moral law in a different way than he could make the laws of mathematics a different way. All of these abstract laws are an expression of His nature and character.
God’s character is the basis for good attitudes. God’s actions are the basis for good behavior. God’s character and morality cannot change because His being cannot change.
God’s knowledge is the basis for the laws of logic, and by consequence the laws of mathematics. He cannot learn or forget. His knowledge is unchanging, and everything He knows must fit together into a coherent account. Logic helps us spot inconsistencies in our own views, the places where our knowledge does not fit together coherently.
God could not make the laws of morality or the laws of logic differently than what they are. God, being who He is, must create as an expression of Himself.
Things being what they are, the laws of morality cannot be any different. We know this intuitively whether we admit it or not. We know some things are right and some things are wrong. That is the way the universe works. We know it full well.
“When a law is created that nobody can follow, its a bad law… Violating an impossible law incurs no debt and any punishment is unjustified.”
Your argument depends on something forcing you to behave in the way you do, to violate your freedom of choice. Since your freedom of choice is never violated, your objections falls apart.
No one or nothing can force you to make any choice. You always choose the very thing you desire most at the time you make a decision in the situation you find yourself in. Your choices in a given situation can be limited, but I cannot ultimately make you do anything.
You always do what you want to do. Your actions are freely chosen according to your most pressing desire at the time you make your choices.
There is nothing outside of us forcing us to sin against our will. It’s not that we cannot keep God’s law; it’s that we will not because we do not want to.
”You said that we receive the forgiveness won by Christ as a gift. A gift is something that is freely given with no obligation or conditions upon the recipient… When you put conditions on your "gift" it's not one.”
I can buy you a brand new BMW 7 Series luxury car. I can make arrangements with an insurance company to pay the insurance for the next five years. I can pay all of the appropriate car tax and licensing fees. I could even give you the money to pay for the gasoline.
I can then present you the keys. If I hold the keys out in front of you, and you do not take them, you will never drive the car. The gift of the BMW must be received, but it is no less a gift.
Eternal life, unhindered fellowship with God in this life and the next, is a gift freely given. But any gift must be received to be of benefit. That’s the way a gift works.
”How does God ‘pay.’ What does God give up? Why does the payment have any meaning when God knows that he will get his son back from the dead anyway? What is God giving for the payment to have any meaning?”
Anytime someone sins against me, they owe me a debt. Anytime someone sins against me, they break a law and should be punished. It is that way in all human relationships because we are made in the image of God.
If you purposely drive your aforementioned BMW (if I can ever get you to take the keys to the darn thing) into my house, you will damage my house. You owe me for the damage (and probably for emotional suffering and a few other things). You are ethically obligated to repair the damage to my home.
If I chose to forgive you freely and completely, I have to incur the costs of repairing my home. I must, in effect, pay the penalty for the damage.
If you did purposely drive your BWM into my house you will have caused me pain. You should have to suffer yourself for the pain you have inflicted.
Almost everyone who has been severely sinned against has felt the right to inflict punishment on the one who has offended him or her. This right to vengeance is a real moral right. We are just when we require it.
If I choose to forgive you, I choose to experience this pain while giving up my right to vengeance. I suffer the pain your actions have caused me without requiring appropriate pain from you.
God must both absorb the cost of sin’s penalty and suffer the pain sin’s punishment brings. God did it by suffering on the cross in the Person of Jesus Christ. Our universe being the kind of universe it is, there could be no other way.
There’s a book on this subject that I would like to recommend: The Reason for God by Timothy Keller. He does a much better job on this topic than me, and much of my answer is borrowed from him.