Let's look at a couple of other passages, and then I will answer your question:
1 Kings 22:1-23 (especially verses 19-23)
I invite you to now refer to the words about Pharaoh in Exodus 3:19 in which God tells Moses He knows the King of Egypt will not let the people go "except under compulsion." And so we then find that God "hardens"Pharaoh's heart in subsequent chapters (e.g. 4:21; 7:3 and elsewhere).
So, what these passages teach me is that while God is a God of love, mercy and patience, His patience has its limits. No wonder the writer to Hebrews reminds us (quoting from Psalm 95:7-11) in Hebrews 3:7-11 -- 'Don't mess with God.' (my words, of course).
Or Elijah challenges the people to "Choose God or another god" (1 Kings 18:21). Or Joshua commanded: "Choose whom you will serve" (Joshua 24:15).
The same message is repeated often in both old and new testaments -- God is not mocked. And therein lies the warning for us. Though He loves us, died for us, pleads for us to return to Him, there comes a point when we harden ourselves to the point that our conscience is 'seared over" like with a branding iron (1 Timothy 4:1-2), and then God permits an evil spirit (I believe a demon spirit. Demons are simply fallen angels. Scripture calls them also 'spirits') -- God permits an evil spirit to torment us.
I also believe the hoped-for result is that the person recognizes he is headed the wrong way and repents. For example, see St. Paul's comment in 1 Corinthians 5:1-5, especially verse 5.
Now turn to 2 Corinthians 2:3-11, where Paul refers to the incident in 1 Corinthians 5.
And so, Saul had rejected God repeatedly. And so God sent an evil spirit to torment him. For what point? To repent, I believe. Likewise, God sent the evil spirit into the mouths of the false prophets who sat in Ahab's court. Ahab was a terribly wicked king who oft refused to repent and was responsible for the deaths of many of God's servants. For what purpose? To repent (why else would Micaiah have told Ahab what God had done, but to get the king to fall on his knees and repent?)
The situation in Job is a little different because God uses Satan to prove for all humanity to read that it is possible for a man or woman to dig in their heels and, regardless of how much hell the devil throws at us, we can still stand for God. His famous words -- "Though He slay me, yet will I trust in Him" (Job 13:15) has been the rallying cry of untold thousands of martyrs through the centuries.
God will use evil to accomplish good.
The passages in Proverbs is like the other ones I cited, for they remind us, there comes a time for each person that God says, "Enough!" And then disaster starts to fall.
Is that person still able to repent and return to the Father? Of course. The only time that becomes impossible is when the person is dead. Then there is no further recourse or hope.
But, the point is, God doesn't want anyone to get that far. Note His words in Ezekiel 18:31-32 and 33:11, and Wisdom 1:13.
Whew. Lots of scripture. I hope I was clear enough in answering your question. If not, what may I clarify?