I haven't found any scriptural evidence to support Calvanism nor the basic tenent of "Once saved, always saved," also sometimes expressed as once God has decided you're saved then there's nothing you can ever do to not be saved. God did predestine that the elect were the one's who would be saved (the elect being those who have heard God's Word and decided of their own free-will to be an obedient Christian), but where Calvin departed was in saying that the elect had no choice in the matter. I've had many Calvinists explain it this way to me: God went through the list of all who would ever be alive on the earth and decided who would be saved and who wouldn't before they were even born, and once the decision was made, those whom God chose couldn't refuse it, and those whom God rejected couldn't ever find favor with God no matter what they did. If God is not a God that desires everyone on the planet earth to be obedient to Him and submit themselves to His Will ("all should come to repentance") in order to be saved, He certainly couldn't be called "loving." To say that the individuals God predetermined before the foundation of the world were the only one's who could be saved, and that they have no choice in the matter and they're saved whether they want to be or not (and vice versa, those who are lost are lost whether they want to be or not), completely elimitates the free-will of the individual to either choose or reject God, which makes God a respecter of persons.
I perceive you do not want to continue this much longer, and I respect that. So I will be brief, and make this my last word (at least in here) on the subject.
I agree that anyone who trusts in Christ has eternal life.
The problem is simply this: Sin has darkened hearts so that no one, apart from God's grace, is able to believe the gospel. Free will, in the sense most people use the term, does not exist. (Martin Luther wrote a great gook on the subject, entitled, "The Bondage of the Will".) People are responsible for their own actions, but Paul was right when he wrote that "the sinful mind is hostile to God. It does not submit to God's law, nor can it do so. Those controlled by the sinful nature cannot please God" (Romans 8:7-8). We are spiritually dead, unless God makes us alive (Ephesians 2:1-5); as such, we cannot believe in Christ. 2 Corinthians 4:4 supports this, because that verse says unbelievers "cannot see the light of the gospel." Note: the problem is not simply that they
will not see the gospel, but rather that they
cannot see it. They need grace before they can even believe the gospel.
For this reason, the Bible says saving faith is a gift of God (Philippians 1:29). Jesus said the act of being born again is accomplished by the Holy Spirit, not by human effort (John 3:5-8). Lydia's heart was opened by the Lord Himself, not any mere human being, according to Acts 16:14. Likewise, repentance, apart from which anyone will perish (Luke 13:3,5), is also a gift of God (Acts 11:18, 2 Timothy 2:25). Since both faith and repentance are gifts of God, He gives them to whoever He wants to give them to, and withholds them from whoever He wants to withhold them from. In the area of salvation, just like everywhere else, God is sovereign. "Our God is in heaven; he does whatever pleases him" (Psalm 115:3). And if God is sovereign, man is not. God controls everything.
The Bible never teaches that the elect are "those who have heard God's Word and decided of their own free-will to be" obedient Christians.
Is God a respecter of persons? No. At the judgment, God will judge righteously. One standard will apply to everyone. But God loves those He chooses to love; by His grace, He makes them able to stand at the judgment. He passes others by. That is Paul's point in Romans 9:10-13: "Not only that, but Rebekah's children had one and the same father, our father Isaac. Yet, before the twins were born or had done anything good or bad—in order that God's purpose in election might stand: not by works but by him who calls—she was told, 'The older will serve the younger.' Just as it is written: 'Jacob I loved, but Esau I hated.'" Did God love Esau as much as He loved Jacob? The answer is obvious. God is under no obligation to do anything for anybody, but He chooses to love some and to save those He loves.
You seem to think that the perseverance of the saints (what some people regretably call eternal security, or "once saved, always saved") is not taught in the Bible. But Jesus said, "I give them eternal life, and they shall never perish; no one can snatch them out of my hand. My Father, who has given them to me, is greater than all; no one can snatch them out of my Father's hand" (John 10:28-29). How long does this eternal life last? Eternally. Not simply until we sin again. Jesus said "they shall
never perish."
Calvinism is simply what the Bible teaches.
