This is a very tough doctrine. I have been reading Robert Haldane’s commentary on Romans, and as you would surmise, I have gotten as far as the ninth chapter. Below are some excerpts from Haldane’s commentary:
“Reprobation includes two acts: the one is negative, which consists in what is called preterition, or the passing by of those who are not elected – that is, leaving them in their natural state of alienation or enmity against God; the other is positive, and is called condemnation, - the act of condemning on account of sin those who have been passed by.
That first act consists in God’s simply withholding His grace, to which no man can have any claim. For this, accordingly, the Scriptures give no reason but the sovereign pleasure of God, who has mercy on whom He will have mercy, and who might justly have left all men to perish in their sins.
In the second act, God considers man as guilty, a child of wrath; and as on this account He punishes him in time, so from all eternity He has ordained to punish Him.
In electing sinners, then, or in passing them by, God acts as a sovereign dispensing or withholding His favours, which are His own, as to Him seemeth good. In condemning, He exercises His justice in the punishment of the guilty. He may impart grace to whomsoever He pleases, without anyone having a right to find fault, since in regard to those whom He destines to salvation He has provided means to satisfy His justice.
On the other hand, those who are guilty have no right to complain if He hath appointed them to wrath, (1Thess. 5:9; 1 Peter 2:8; Jude 4 ;) for God was under no obligation to exercise mercy towards sinners. Both these doctrines of election and reprobation are exemplified in the case of Jacob and Esau, in which there is nothing peculiar. Jacob was loved and chosen before he was born, and Esau before he was born was an object of hatred and reprobation. Under one or the other of these descriptions, all who receive the above doctrines must be convinced that every individual of the human race is included.”
“Unless men reject the Bible, they must admit that all were condemned in Adam; and if they were justly condemned, there can be no injustice in leaving them in that state of condemnation, and punishing them as sinners. It is only from the sovereign good pleasure and love of God that any of the human race are saved. He had no such love to the fallen angels, and they all perished; nor has He such love to those of the human race that shall perish, for He says, ‘Depart from Me, ye cursed, I never knew you.’ Men had no more claim upon God for mercy than the angels.”
“The doctrine of the Sovereignty of God is derogatory to the pride of man; it lays all his high notions of independence in the dust, and reduces him, when acknowledged, to a sense of his utter helplessness and misery. Happy, nevertheless, are they who have learned this lesson, for it is one which flesh and blood cannot teach, but only our Father which is in heaven. In light of this chapter they see themselves as lying entirely in the hand of God, having nothing that distinguishes them from others, but His sovereign will and favour in their election.”
“Whatever difficulties are found in the doctrine of the sovereignty of God, and in the truth that He ordains for His own glory whatever comes to pass, yet this, it is clear, is the doctrine of Scripture from beginning to end. Every part of it represents God as ordering and directing all events, and without this, and were anything left to depend or be regulated by the will of His creatures, He would cease to be the Supreme Ruler.”
Haldane concludes his chapter on Romans nine with the following sentence:
“If we lose sight of sovereignty, we lose sight of God.”
“As it is written, Jacob have I loved, but Esau have I hated.
What shall we say then? Is there unrighteousness with God? God forbid.
For he saith to Moses, I will have mercy on whom I will have mercy, and I will have compassion on whom I will have compassion.
So then it is not of him that willeth, not of him that runneth, but of God that sheweth mercy.
For the scripture saith unto Pharaoh, Even for this same purpose have I raised thee up, that I might shew my power in thee, and that my name might be declared throughout all the earth.
Therefore hath he mercy on whom he will have mercy, and whom he will he hardeneth.
Thou wilt say then unto me, Why doth he yet find fault? For who hath resisted his will?
Nay but, O man, who art thou that repliest against God? Shall the thing formed say to him that formed it, Why hast thou made me thus?
Hath not the potter power over the clay, of the same lump to make one vessel unto honour, and another unto dishonour?
What if God, willing to show his wrath, and to make his power known, endured with much longsuffering the vessels of wrath fitted to destruction:
And that he might make known the riches of his glory on the vessels of mercy, which he had afore prepared unto glory.” ~ Romans 9:13-23