I think that Paul's teachings of "Salvation by Grace" are used to create a sinister distortion of the true Grace of God, as well as a distortion of God's Justice.
A Distortion of Grace
According to Paul, God requires death and blood as a payment for sin. (Romans 6:23) The system of animal sacrifice in the Mosaic law is reinterpreted by followers of Paul as a system of death by proxy, and the inferior Mosaic sacrifice of animals is eventually replaced with the infinite and superior "New Testament" sacrifice of a Divine being: Jesus. The idea is that in order for Justice to be fulfilled, God requires the payment for each sin to be exacted, and Jesus has become the payment for the sins of all those who accept him.
The problem with this? YHVH is a god of Love, and He is more capable than any human being. The truth of the Mosaic system is this: God commanded us to Love him. We show our love for Him by obeying Torah, by following Mitzvot (Commandments.) When we make mistakes, he offers true forgiveness for us. Animal sacrifices were offered in order to give up our good things to God, as a token of our love. The forgiveness that he offers is true because it isn't about displacing punishment onto another, its about forgiving.
Have you ever been really angry at someone? Perhaps you've wanted to hit them? God asks us to forgive our fellow men. Does this mean we should take out our anger by hitting a stand-in so that the one who offended doesn't need to pay? No. That is just redirection of anger. No forgiveness happened, the wrath merely got redirected. We forgive our fellows by extending mercy towards them, by giving them a second chance. If we, being human, can muster up the strength to do this virtuous thing, certainly God can do it, too!
So the truth is that God can really forgive you! Just pray and ask him for it. The catch is, that you must really be sorry, and you must be serious about not repeating your sins. This expression of our sorrow and re-commitment to follow Torah is the repentance that Jesus, John the Baptist, and dozens of prophets of the Hebrew Scriptures called people unto.
A Distortion of Justice
Even though God extends mercy to us for our honest mistakes, he is a fair and righteous judge. Paul's teachings are used to distort justice by people who teach that it is not by works (following mitzvot) that we are saved but by "grace alone" through faith on Jesus Christ.
A Pauline Christian can imagine someone who robs, steals, cheats, bears false witness, covets, and also accepts Jesus Christ as their savior to be "covered" by the grace of Jesus.
They also see someone who follows all the mitzvot, loves God and their neighbor, feeds the hungry and clothes the naked going to Hell because they did not accept Jesus Christ as their savior, justifying this by the statement that "All have sinned and fall short of the glory of God."
Jesus taught ethics. He promised people that they were near to the Kingdom of God when they lived according to the Torah and demonstrated love to their fellows. Jesus actively forgave sins during his life, telling people to go and sin no more! He never spoke about suffering to take on all sins by proxy at his death. That doctrine didn't exist until Paul taught it. He did, however, die because of (from) people's sins. Sin was the cause of his death.
By teaching grace alone (and contradicting James even on the subject of Abraham's justification), Paul opens the door for the permissibility of sinfulness, corruption, selfishness, etc. It is true that a grace-alone believer can truly repent, and live by God's law, and become sanctified, but without works there is no attempt to fulfill mitzvot, and the person living in faith without works is therefore failing in the first commandment, to love the LORD thy God.
If you serve God with a sincere heart, he will become your deliverance, and you need not fear. He is the most Just of all judges, because he can weigh your heart in the balance together with the evidence of your actions.
In Defense of Babylon
There is one point I would like to explain on behalf of the so-called Christians. I am not sure if they even understand this, because I never did until recently, but three of their doctrines add up to eliminate some of the ill logic described above. Protestants typically believe that the believers constitute the "Body of Christ" and because of this, Christ isn't a Proxy (in your behalf), but rather is a reinforced part of your own self, thus God is punishing "you" (the Body of Christ) for your own sin. (Does this mean that the Body of Christ is a sinful being?) And, on the other side, the Trinity equates Jesus with the Father, which means instead of punishing you, he's taking the punishment upon an aspect of himself. This is supposed to reconcile the problems with true forgiveness and proxy punishment that I mentioned above. It is a clever attempt made by the philosophies of men, but it fails to measure up adequately to the simplicity and beauty of a true system of repentance and forgiveness.
To Sum Up
It turns out that the God of Israel is a God of Love, offering genuine mercy and forgiveness, and perfect justice, while the Christ-God of Pauline Christianity is a bloodthirsty, vengeful being, that doesn't have a heart big enough to forgive but instead must kill his own innocent son in order to let the wicked run free.
Please, tell me if I've gotten this wrong!
10 months ago