My preacher keeps saying "Once Saved Always Saved" but I disagree with this. When asked how he comes to this conclusion he always goes to Hebrews 13-5. Now he may not leave me nor forsake me but that doesn`t mean I won`t leave him or forsake him. Even though I never will. I believe Matthew 7-21 where it states 'Not every one that saith unto me, "Lord, Lord shall enter into the kingdom of heaven." So can a man be saved forever but lose his salvation?
You are very observant concerning the scriptures. If your preacher is using Hebrews 13:5 to prove the "once saved, always saved" doctrine, he is taking that passage out of context. The verse, taken as a whole, is saying not to covet more physical blessings than you have because having God is sufficient, regardless how rich or poor you are.
It has been said that over 200 separate passages of scripture argue that once one has been saved, he may still be lost. (By having been saved I mean one has had his former sins forgiven by the blood of Christ and has begun to "walk in newness of life" (Rom 6:4).)
Among the passages more often quoted to support the "once saved, always saved" doctrine is the scripture in Romans 8:38-39: "For I am persuaded, that neither death, nor life, nor angels, nor principalities, nor powers, nor things present, nor things to come, Nor height, nor depth, nor any other creature, shall be able to separate us from the love of God, which is in Christ Jesus our Lord." Nothing can separate us from the love of God, but we can separate ourselves from the salvation which is in Christ.
There are many passages that support the idea that Christians may "fall from grace." One is the passage that uses that phrase, Galatians 5:4. Here Paul is talking to Christians who wanted to keep the Old Testament commandments to the Jews and saying they could be justified by them. To these people who had received salvation, he says that if they rely on circumcision or other legalistic practices they are "fallen from grace." If you can't fall, how could Paul say they had?
Other passages warn of the possibility. "Wherefore the rather, brethren, give diligence to make your calling and election sure: for if ye do these things, ye shall never fall." (2 Pet. 1:10) "But I keep under my body, and bring it into subjection: lest that by any means, when I have preached to others, I myself should be a castaway." (1 Cor 9:27) "Wherefore let him that thinketh he standeth take heed lest he fall." (1 Cor. 10:12)
Perhaps the most notable passage on the subject is the entire book of Jude. He warns of those who are Christians who are leading other Christians into all manner of evil. If it was not possible for them to fall from their saved state, why would he find it necessary to change from what he originally intended to write and instead warn them against something they could not do?
The biggest problem I have with most who follow the idea of "once saved, always saved" is that they must also accept the doctrine that God preselected those who would be saved and they have nothing to say about it. The other side of the coin is that God determined ahead of time that most people would not be allowed to choose to be saved, and therefore they will be punished because of what God chose for them. Such an arbitrary God is neither just nor merciful. Worse, he sent his only Son to die unnecessarily, for if he had already made the choice, Jesus blood has no effect.
Thank you for an excellent question.