I would respond to John 17 about Jesus not praying for the world in a simple way that: Of course Jesus only prays for the sheep, not the goats. Thats not to say people FROM the world cant repent and be shown to be sheep! Born again
But what does 2 Cor 5:20 mean then? Why does Paul say be ye reconciled if they already ARE? Would you take the "world" in 2 Cor 5:19 to be world as the elect instead of every person?
I'm sorry...that kind of answer begs the question. It implies that Jesus didn't know who all his sheep were! He only knew some of his sheep by name -- not all of them -- the goats that have this inherent ability to repent, he didn't know who they were, so he didn't pray for them?. Sorry...that doesn't make sense to me.
What Paul is saying is typical New Covenant language. The command to "be reconciled to God" in v.20 follows what Paul said God had already accomplished in or through Christ. Orthopraxy always follows on the heels of Orthodoxy. This is why in Paul's epistles, he first expounds on Doctrine -- then transitions to Practice. This is because acceptable Practice must be find its ground, it's motivation, its intentions in what God has already done in Christ for us, to us, in us or through us. He's telling the church that since Christ has reconciled YOU, make sure you understand God's expectations -- that He expects you to live a life whereby you reciprocate in kind what He has already done for you.
These kinds of commands or exhortations are so often given in the NT so that hearers of the Word can confidently affirm to their own hearts that God has actually done a great work in them.

