-Why does paying for someone else sins redeem them even though they didn’t pay the price?
In the Book of Ruth, God sets up the concept of Kinsman-Redeemer. Only a relative could redeem another. This means that, according to His own law, in order to redeem mankind, God would have to become a man! And that is exactly what He did, as Jesus Christ.
Galatians 4:4-6
But when the time had fully come, God sent his Son, born of a woman, born under law, to redeem those under law, that we might receive the full rights of sons. Because you are sons, God sent the Spirit of his Son into our hearts, the Spirit who calls out, "Abba, Father."
Redemption is all about the family relationship. God wanted to expand His family, and gain more sons. He already had one unique Son in Jesus Christ, but He wanted to adopt many more sons. In this way, think of redempion as the purchase price for adoption.
-Why is paying for someone else’s sin just? If it isn’t, why is God being unjust?
Not just anyone could pay for a person's sin. An innocent substitute was necessary, according to Mosaic law. Uh oh, we have a problem:
Hebrews 10:4
because it is impossible for the blood of bulls and goats to take away sins.
Again, a kinsman-redeemer is necessary to take away the sins of man. But no man could be found who was worthy; that is, totally innocent! Until Jesus came along, that is.
1st Corinthians 5:7
Get rid of the old yeast that you may be a new batch without yeast—as you really are. For Christ, our Passover lamb, has been sacrificed.
The Old Testament sacrifices pointed to the one greater sacrifice that would be made. So why was God just in having Christ pay for our sins? Because God was willing to pay the price of redemption, in order to gain more children. An exchange was made at the cross: Christ took the sins of mankind upon Himself, paying for them, while giving those who would believe in Him His righteousness:
Romans 4:24-25
"but also for us, to whom God will credit righteousness—for us who believe in him who raised Jesus our Lord from the dead. He was delivered over to death for our sins and was raised to life for our justification."
-How can you pay for future sins when they haven’t happened yet?
God already exists in the future, which is why this can be said about Him:
Romans 4:17
"As it is written: 'I have made you a father of many nations.' He is our father in the sight of God, in whom he believed—the
God who gives life to the dead and
calls things that are not as though they were."
-Why is Jesus’ payment for billions, trillions, or even quadrillions of people’s sins finite (great, but finite) when if we don’t accect this payment we have to make the infinite payment of eternal damnation just for our own sins?
Jesus' sacrifice wasn't finite. God's grace (unmerited favor) is greater than all the sins ever committed.
Romans 5:20
The law was added so that the trespass might increase. But where sin increased, grace increased all the more,
-Why does anybody have to pay for our sins anyway?
Have to? Well, God didn't. That He did, shows how much He loves us.
-This only applies to a few of you but: Why are you not open minded to what you believe being wrong even though there is so much logic against it?
Man's logic is faulty; God's ways are perfect.
1st Corinthians 2:13-15
This is what we speak, not in words taught us by human wisdom but in words taught by the Spirit, expressing spiritual truths in spiritual words. The man without the Spirit does not accept the things that come from the Spirit of God, for they are foolishness to him, and he cannot understand them, because they are spiritually discerned. The spiritual man makes judgments about all things, but he himself is not subject to any man's judgment:
For the record, the Bible is just a collection of books written by humans of fresh and blood just like us.
Not exactly. The Bible is a book written by men, yet whose author is God.
2nd Peter 1:21
For prophecy never had its origin in the will of man, but men spoke from God as they were carried along by the Holy Spirit.
Moreover, the Bible was a chosen collection of books approved by the Church.
The Church did not organize the Bible. God the Holy Spirit did.
What did the Church did to the rest of books that they deemed anti-God or not speaking in God best interests? They destroyed them, of course.
Ever heard of
Phaenomena, by Aratus? Next to Homer's
Iliad and
The Odyssey, Phaenomena is perhaps the 3rd most-important work of ancient Greek literature. We have copies of it today. And the Bible quotes from it!