Just passing through for now, will get back in more detail later. I found this site that gives a good introduction to this historical debate.
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Conditional security” is a theological term used in reference to the salvation of believers in Jesus Christ. It describes the supposedly tentative quality of the Christian’s salvation. In other words, a Christian’s salvation is “conditionally secure.” This begs the question: upon what condition is the believer’s salvation secure? Proponents of conditional security assert that the salvation is conditional upon remaining faithful until the very end. To use an analogy the Bible uses, the athlete must finish the race in order to receive the prize. To support this view, those who adhere to the doctrine of conditional security would point to such biblical passages as the following:
“And many false prophets will appear and deceive many people. Because of the increase of wickedness, the love of most will grow cold, but he who stands firm to the end will be saved.” (
Matthew 24:11-13)
“So therefore, brothers, we have an obligation—but it is not to the sinful nature, to live according to it. For if you live according to the sinful nature, you will die; but if by the Spirit you put to death the misdeeds of the body, you will live, because those who are led by the Spirit of God are sons of God.” (
Romans 8:12-14)
“Now, brothers, I want to remind you of the gospel I preached to you, which you received and on which you have taken your stand. By this gospel you are saved, if you hold firmly to the word I preached to you. Otherwise, you have believed in vain.” (
1 Corinthians 15:1-2)
“Do not be deceived: God cannot be mocked. A man reaps what he sows. The one who sows to please his sinful nature, from that nature will reap destruction; the one who sows to please the Spirit, from the Spirit will reap eternal life. Let us not become weary in doing good, for at the proper time we will reap a harvest if we do not give up.” (
Galatians 6:7-9)
These passages, and many others that could be cited, point to the conditional quality of the believer’s salvation. In each of these passages, the biblical author (under the inspiration of the Holy Spirit) uses conditional language (e.g., if you endure, then you will be saved) to highlight the nature of the believer’s security in Christ. In order to ensure the security of our salvation, the believer must: 1) Endure to the end; 2) live by the Spirit; 3) hold fast to the preached word; and 4) sow to the Spirit. It’s not as if the gift of salvation is lacking in any way, but the individual believer must earnestly strive to remain faithful. In the words of Paul, “work out your own salvation with fear and trembling” (
Philippians 2:12).
Given the weight of the biblical evidence, it would seem that the view of conditional security is unassailable. How could anyone argue with the notion that the believer must remain faithful until the end to secure his salvation? Yet, there is another side to this debate. This is the age-old theological debate between Arminians (those who hold to conditional security) and Calvinists (those who hold to what it called “eternal” security or Perseverance of the Saints)" Taken from:
https://www.gotquestions.org/conditional-security.html