Evangelicals are often accused of "proof-texting" - quoting a single verse to prove something, often without considering the context. In my experience, while evangelicals are sometimes guilty of it, it's often non-evangelicals who do it more dangerously, to the extent in some extreme situations of building entire systems of doctrine on one verse (e.g. "God is love") without considering how it fits into the theology of the rest of the Bible.
Someone (it may have been David Jackman) once cleverly said:
A text without a context is a pretext for a subtext.
When we cite verses, it's really important that we understand how they fit into their context - that often makes it much easier to see how we should understand them.
I recently received a comment on this post, which raises several interesting issues about how we understand the Bible and so on, so I thought I'd respond to it here rather than in situ.
"The doctrine of penal substitution states that God gave himself in the person of his Son (Jesus) to suffer instead of us the death, punishment, and curse due to fallen humanity as the penalty for sin."
Hmmmm........ if your idea is true the crucifixion of Jesus would have been the resolving end of all issues between you and God. However Jesus says that the issue of guilt relative to sin remains as the outstanding issue between you and God AFTER his crucifixion. What have you to say about Jesus' statement in Jn. 16:8?
God says in Gen. 9:5 NIV (the NIV being about the clearest on this point) that whenever any man looses his life by bloodshed God demands (requires) an accounting. What would you think the required accounting might be?
There is at least one sin that must be repented of to obey the Acts 2:38 command. What do you think think this sin might be relative to the outstanding issue in Jn. 16:8?
Heb. 7:12 says that a change has been made to the law of God and Rom. 5:20 says a law has been added. What law?
First up, it's not my idea. The idea of Penal Substitutionary Atonement dates back at the absolute latest to the letter to the Hebrews (1st century AD), and I'd argue it was actually God's idea before the universe began. But anyway...
As far as I can see, John 16:8 doesn't bear much relevance to the discussion at all:
But I tell you the truth: It is for your good that I am going away. Unless I go away, the Counselor will not come to you; but if I go, I will send him to you. When he comes, he will convict the world of guilt in regard to sin and righteousness and judgement: in regard to sin, because men do not believe in me; in regard to righteousness, because I am going to the Father, where you can see me no longer; and in regard to judgement, because the prince of this world now stands condemned.
John 16:7-11, NIV
Verse 8 says that the Holy Spirit, when he comes, will convict the world of guilt. In John, the world "world" (κοσμος) refers either to the world in rebellion against God (e.g. 1:10, 7:7) or to the world as the scope of Jesus' salvation. In Jesus' long discourse which contains John 16, "world" almost always means the world as opposed to Christians (e.g. 15:19 - "If you belonged to the world, it would love you as its own. As it is, you do not belong to the world, but I have chosen you out of the world. That is why the world hates you.").
So the Holy Spirit convicting the world of sin is telling those who are not disciples - i.e. are not followers of Jesus, that they are sinners. There's a strong world / disciples distinction in this passage.
Next, the commenter writes that "if your idea is true the crucifixion of Jesus would have been the resolving end of all issues between you and God". That simply isn't true. My appropriation of the benefits of the crucifixion would be the resolving end of all issues between me and God, rather than the crucifixion itself.
Simple analogy - suppose that someone invents an armour that is completely impervious to bullets. Does that mean the end of all deaths from bullets from that time onwards? No - it requires the use of that armour rather than just its invention, which is precisely what Acts 2:38 talks about.
And in a sense, we never get to fully appropriate the benefits of the crucifixion until we have reached full union with Christ by our own participation in his death by our death...
Genesis 9:5 is an interesting verse to cite. God says, speaking to Noah after the flood, that he holds people responsible for each others' lives - that he will "demand an accounting". (ESV is "require a reckoning", which is much the same). So God holds us accountable for each other's lives. Which is precisely why we need someone to take the punishment demanded by that accounting. We are all guilty and complicit of abusing others - not speaking out (lovingly) against abortion or unjust war, exploitation of child labour and death, living off the profits from exploiting others, hatred, using other people for our own selfish ends. Genesis 9:5 says God will hold us accountable. So we all need someone to take the penalty that we deserve.
Romans 5:20 (in context) is quite clearly talking about the role of the Mosaic Law given to Israel in the wilderness to show them how to respond to God's salvation of them in the Exodus. It served largely to show that they were sinners and needed an even better salvation. Hebrews 7:12 (in context) clearly speaks about the removal of that covenant because of Jesus' death. I've written more about the whole issue of Christians and the Old Testament Law, but I fail to see the relevance of these verses if they are understood in context.