I agree with all those verses, like I said I believe in eternal security. I am not saved by works, nor is my performance able to somehow remove salvation. I am elected before the foundation of the world. However, I can choose of my own free will not to be saved, and by simply losing faith in God, or the gospel message and maybe even the Bible in general. A calvinist will come and say, " you were never saved." But I know I was. I believe the Bible warns of apostacy. Why would they warn of apostacy of the non saved? An athiest isn't an apostate, unless like I said, they were a former believer who lost their faith. The majority of X, Y, and Z generations are losing their faith as soon as they enter college. They encounter skepticism for the first time, and are forced to move from faith to logic over night, and the result is not pretty. Some of them return to the faith later, the majority do not. So we are losing alot of christians to apostacy, I think it is an important topic.
You do an excellent job of listing out scripture in support of the truth you must remain faithful to the end, but a person can get around these scriptures by arguing:
1. People who are not faithful at the end of their life never were converted.
2. You are selling a work bases salvation.
3. There are different “salvations” and say things like “Ananias and Sapphira” were punished with death, but go on to heaven salvation. (They do not explain how death suddenly became a punishment for Christians who get to go home?)
4. Christ will not loss any.
I use other scripture to address these arguments.
1. Gal. 6: 8 Whoever sows to please their flesh, from the flesh will reap destruction; whoever sows to please the Spirit, from the Spirit will reap eternal life. 9 Let us not become weary in doing good, for at the proper time we will reap a harvest if we do not give up. 10 Therefore, as we have opportunity, let us do good to all people, especially to those who belong to the family of believers.
Paul explains plainly that eternal life is the harvest in the future we do not want to “give up”, but that also teaches we can give it up.
Our doing good stuff while here on earth (or better: our allowing God to work through us doing good stuff) is not to “earn”, “payback” or to allow us to “hold on to our salvation”. We want to continue to utilize Godly type Love and not get caught up in carnal type love so the huge Love Feast of Heaven (unselfish type Love only) still has value to us and not something we would sell on the cheap.
As far as being saved by faith only without “works”, that is true, but just like the Prodigal son wimped out of taking the punishment he fully deserved and humbly returned to the Father, we must wimp out, give up surrender to our enemy God and that will allow God to shower us with His charity.
2. Eternal Life in heaven is spoken of as our inheritance and not something we actually have at the moment. All other Gifts of God we have right away, but heaven is truly ours as a birthright (our inheritance).
Part of the meaning to the concept of being given a gift is the fact that the ownership of the gift actually transfers to the receiver of the gift and as such the receiver of the gift can do what he/she wants to do with the gift.
The Hebrew writer in Heb. 12:16 See that no one is sexually immoral, or is godless like Esau, who for a single meal sold his inheritance rights as the oldest son.
Esau own the “gift” of the first born inheritance rights, which could not be taken from him by anyone, nor could someone steal it from his hand, not even his father could take them back, but Esau could sell it or give it away.
The Hebrew writer is telling us not to give away or sell our birth right (as born again Christians) which is our inheritance of eternal life.
We own a paid up tax free deed to a home in heaven, so that home was gifted to us, but the Hebrew writer is saying we could sell (or give it away) like Esau did.
Again we are not doing or allowing the Holy Spirit to do good stuff through us to get anything (God has given us everything up front with the exception of dwelling in heaven right now, but we do have an undeserved birthright to heaven which cannot be lost like your keys, stolen from you, earned, paid back and even God will not take it from you, but you can of your own free will which you still have given it away (satan wants it).