I don't think very highly of Calvin's theologies. I like Wesley much better. One should read his works. I know a lot of people that believe in Calvinism believe by blind faith. They take a verse out of context, show it to a christian and say "do you deny that the bible says it" type of thing. Here's a explanation from my point of view of Roman's 9
Romans 9
God's Sovereign Choice
1I speak the truth in Christ—I am not lying, my conscience confirms it in the Holy Spirit— 2I have great sorrow and unceasing anguish in my heart. 3For I could wish that I myself were cursed and cut off from Christ for the sake of my brothers, those of my own race, 4the people of Israel. Theirs is the adoption as sons; theirs the divine glory, the covenants, the receiving of the law, the temple worship and the promises. 5Theirs are the patriarchs, and from them is traced the human ancestry of Christ, who is God over all, forever praised![
a] Amen.
First Paul establishes that he speaking of Israel. That is the subject.
6It is not as though God's word had failed. For not all who are descended from Israel are Israel.
He's saying that God did save those that were the real Israel.
7Nor because they are his descendants are they all Abraham's children. On the contrary, "It is through Isaac that your offspring will be reckoned."[
b] 8In other words, it is not the natural children who are God's children, but it is the children of the promise who are regarded as Abraham's offspring.
The real Israel and Abraham's children are those that are "of the promise." What promise was he speaking of? The promise of the messiah and Christ Jesus, God amoung us who would save us. In other words, those who did not reject Him.
9For this was how the promise was stated: "At the appointed time I will return, and Sarah will have a son."[
c]
10Not only that, but Rebekah's children had one and the same father, our father Isaac. 11Yet, before the twins were born or had done anything good or bad—in order that God's purpose in election might stand: 12not by works but by him who calls—she was told, "The older will serve the younger."[
d] 13Just as it is written: "Jacob I loved, but Esau I hated."[
e]
Israel's election was by birth. Those who were the "elect" were called so because they were "born into" it. Same with inheritance, it was granted to the first born and had nothing to do with faith, merit, or love of the parent. God is demonstrating here that he's is going to take the "birthrite" out of the hands of the one's that he hates (those that reject him) who were natually born into it and give it (election) instead to the one he loves (those that chose him).
14What then shall we say? Is God unjust? Not at all! 15For he says to Moses,
"I will have mercy on whom I have mercy,
and I will have compassion on whom I have compassion."[
f]
Yes, it is
His decision on who becomes the elect, not some rule of the location of one's birth. He can take their "birthrite" if he so choses. God CAN have mercy on whom he wants to have mercy on. And as the scriptures say, he CHOSES to have mercy on those that chose him (Christ).
16It does not, therefore, depend on man's desire or effort, but on God's mercy.
This basically says that without God's mercy, no amount of man's effort and goodness could possibly save him. It is because he GIVES mercy at all that anyone is saved.
17For the Scripture says to Pharaoh: "I raised you up for this very purpose, that I might display my power in you and that my name might be proclaimed in all the earth."[
g]
Pharaoh is a good example to those that do not believe and chose to be God's enemy. It was not that Pharaoh was God's enemy because God created him that way, but because Pharaoh chose to be. God raised him up finanically, making his empire very great, then hardened his heart so that he would continue his stubbornness and so that God could show the objects of love his glory and the objects of his wrath what kind of punishment his enemies (those that chose to be so) will recieve.
18Therefore God has mercy on whom he wants to have mercy, and he hardens whom he wants to harden.
19One of you will say to me: "Then why does God still blame us? For who resists his will?" 20But who are you, O man, to talk back to God? "Shall what is formed say to him who formed it, 'Why did you make me like this?' "[
h] 21Does not the potter have the right to make out of the same lump of clay some pottery for noble purposes and some for common use?
God could have just left pharaoh a commoner, a common king, but instead, by raising him up and hardening his heart to do things he normally wouldn't do, he was made for a "noble" purpose to be used by God.
The same with hardening the Jews who rejected Christ, he hardened their hearts so that they would no only reject Christ, but they would crucify Him as well, serving a purpose of salvation for all people, which is a noble purpose.
22What if God, choosing to show his wrath and make his power known, bore with great patience the objects of his wrath—prepared for destruction? 23What if he did this to make the riches of his glory known to the objects of his mercy, whom he prepared in advance for glory— 24even us, whom he also called, not only from the Jews but also from the Gentiles?
Who are the objects of his wrath? those that reject Him as God and savior. Who are the objects of his mercy? Those that choose Him and obey Him.
25As he says in Hosea:
"I will call them 'my people' who are not my people;
and I will call her 'my loved one' who is not my loved one,"[
i] 26and,
"It will happen that in the very place where it was said to them,
'You are not my people,'
they will be called 'sons of the living God.' "[
j]
He is speaking of the gentiles that will come into salvation.
27Isaiah cries out concerning Israel:
"Though the number of the Israelites be like the sand by the sea,
only the remnant will be saved.
Was there a remnant that believed and were saved from Irsael?
28For the Lord will carry out
his sentence on earth with speed and finality."[
k]
29It is just as Isaiah said previously:
"Unless the Lord Almighty
had left us descendants,
we would have become like Sodom,
we would have been like Gomorrah."[
l]
30What then shall we say? That the Gentiles, who did not pursue righteousness, have obtained it, a righteousness that is by faith; 31but Israel, who pursued a law of righteousness, has not attained it. 32Why not? Because they pursued it not by faith but as if it were by works. They stumbled over the "stumbling stone." 33As it is written:
"See, I lay in Zion a stone that causes men to stumble
and a rock that makes them fall,
and the one who trusts in him will never be put to shame."
righteousness by faith instead of by works. It is God that justifies the faithful. All men are sinful, so that no one can be righteous by obeying the law, they need a righteousness that is From God and is given to those that believe.
it continues on into chapter 10 and 11 like this, speaking of Irsael. Calvinism has come about through a lack of understanding.