- Christians possess the freedom to turn away from God, thus "losing" their salvation.
- Christians possess "eternal security" and need not worry about "losing" their salvation.
- Christians have Christ and need not worry about losing Christ because Christ is faithful.
- Christians can turn away from Christ, thus forfeiting Christ, because humans are not always faithful.
"Security and apostasy" is just another way of saying "God is faithful and humans are not." It's another way of saying "Trust in the LORD and not in yourself." It is another way of saying "Fix your eyes on Jesus, the author and perfecter of your faith," and "take care lest you should fall." Again as it says "Nothing can snatch his sheep from his hand" but "all we like sheep have gone astray." Look up all the passages on security and see whether they do not all point out God's faithfulness. Look up all the passages on apostasy and see whether they do not all point out human waywardness. These are both true and both need to be preached and taught and known and believed. The idea that they contradict each other only comes in when someone tries to detach these things from Christ and tries to turn the question into, "Do I have salvation?" But there is that deadly and wrong-headed separation embedded right in the question, to take Christ out of the question of salvation, to imagine that it's possible to only imply him or assume him here instead of bringing him to the forefront as the entire point of the question and the entire answer as well. If the question "Do I have salvation" does not mention Christ, then where is the understanding that Christ *is* our salvation? Where is the understanding that the grace of God is not by works or by efforts or by our will but through Christ? When people find this question perplexing, it is often because Christ is not mentioned in the question and not remembered in the answer.
Steps back off soapbox ...