Job admitted the omnipotence of the LORD, and that nothing could get in the way of His purposes. God is fully able to do anything, but never does anything foolish, because He is also righteous and omniscient. He does that which is in the context of His character, and He is always true to Himself.
We cannot tell God to do something contrary to His own wise purposes as if He were our errand boy. We must always trust on His much wiser judgement in all the circumstances of our lives. For the same reason we must not complain to God in adversity, as if God had been mistaken in allowing it to happen to us. This is where Job had gone wrong.
Job referred to the LORD's earlier questions to him (Job 38:2, 3), and openly and unreservedly admitted that he had been talking about things he didn't know anything about. He now knew that he had been complaining to God about what he couldn't possibly understand, things which were too wonderful for him, of which he was ignorant.
Job had implied before that God somehow lacked in wisdom and understanding by submitting him to terrible suffering. Now he had a new conception of God: he realised that he was in no position to question God in anything that He did.
He said that he had formerly heard of God - probably through the tradition coming from the earliest ages. But now he had actually seen the LORD with his own eyes, probably one of the theophanies which the Old Testament gives witness to.
In the beginning of the book, Job was said to be "blameless", and he evidently was proud of his own righteousness, judging by his speeches recorded in the book. But now he abhorred himself, when his eyes were opened to his insignificance and poverty in the sight of God. But this is the experience of God's saints throughout the ages. D L Moody wrote that "the more one grows in grace, the meaner he is in his own eyes".
Seeing the glory of the LORD, he now saw himself as he really was, vile - and he abhorred himself, repenting in dust and ashes. We note here the steps of real repentance, in faith:
When we accept the evidence that we are sinners and unworthy of the presence of God, and we give up trusting on our own merits and no longer try to live in our own way, but turn to the living God, that is true conversion.
Job was humbled, recognised the sovereignty of the LORD, confessed his arrogance and repented. This was his conversion, and in this way the LORD accomplished His purpose in the life of Job. Job had come to see himself in the light of the presence of the LORD. "If we say that we have fellowship with Him, and walk in darkness, we lie and do not practice the truth. But if we walk in the light as He is in the light, we have fellowship with one another, and the blood of Jesus Christ His Son cleanses us from all sin." 1 John 1:6,7 (NKJV)
1 Then Job answered the LORD and said:
2 "I know that You can do everything, and that no purpose of Yours can be withheld from You.
3 You asked, 'Who is this who hides counsel without knowledge?' Therefore I have uttered what I did not understand, things too wonderful for me, which I did not know.
4 Listen, please, and let me speak; You said, 'I will question you, and you shall answer Me.'
5 "I have heard of You by the hearing of the ear, but now my eye sees You.
6 Therefore I abhor myself, and repent in dust and ashes."