Hi! I come from a Presbyterian background, and I've recently been having trouble with the Reformed doctrine of penal substitution. The go-to verses that they cite are:
-Romans 3:23-26 - "All have sinned and fall short of the glory of God; they are now justified by his grace as a gift, through the redemption that is in Christ Jesus, whom God put forward as a sacrifice of atonement by his blood, effective through faith. He did this to show his righteousness, because in his divine forbearance he had passed over the sins previously committed; it was to prove at the present time that he himself is righteous and that he justifies the one who has faith in Jesus." (NRSV)
-2 Corinthians 5:21 - "For our sake he made him to be sin who knew no sin, so that in him we might become the righteousness of God." (RSV)
-Galatians 3:10, 13 - "All who rely on works of the law are under a curse; for it is written, 'Cursed be every one who does not abide by all things written in the book of the law, and do them.' ... Christ redeemed us from the curse of the law, having become a curse for us - for it is written, 'Cursed be every one who hangs on a tree'" (RSV)
-1 Peter 3:18 - "For Christ also died for sins once for all, the righteous for the unrighteous, that he might bring us to God" (RSV)
There are a few more, too, but these seem to be the big ones. The doctrine of penal substitution is one of the main things that drove me away from Calvinism in the first place, mainly because it doesn't make sense. However, I still can't answer anybody who brings these verses up as "proof" that the reformers were right. Any ideas?