The question: A recent visitor to my site asked the question:  "'once saved always saved' - do you believe this?"

My answer: The simple, incomplete answer to this question is 'yes', but the answer is really much more complex than that. Here is a more complex answer:

Those who have been born again, that is, those whom the Spirit of God has regenerated, can never be lost. God is keeping salvation safe for them and God is keeping them safe for salvation [1Peter 1:3-5].
But this assurance does not and cannot apply to people whose 'faith' God knows is not true faith [read John 2:23-25]. Because of this I avoid saying 'once saved always saved'. It is better to say 'once truly saved always saved'.
Three times the New Testament tells us that our salvation is guaranteed [Romans 4:16; 2Corinthians 1:22; 5:5].The first study listed on my site - Assurance of Salvation - is a collection of multiple New Testament verses that affirm the eternal security of all true believers. I created this study in response to a friend's distress caused by her home group leader teaching that salvation can be lost.
In addition, this study in the Salvation and the Work of Christ study series also affirms assurance of salvation. It contains quotes from churches and people who teach that salvation can be lost, and quotes from churches and people who teach salvation is secure, and exposes the wrongness of the belief that salvation can be lost.
(These two studies give an even more comprehensive answer to the question. Anyone who really wants to understand the security of salvation in Christ is advised to read and think deeply about the scripture text addressed in these studies.)
So yes, I believe in the eternal security of the believer, that is, of the true believer. All of my studies reflect this truth.
But, like the New Testament, there is also a necessary caution - that if a person's claim to believe in Jesus Christ is biblically genuine, then that belief will be evident in the way the person lives. A person who claims to believe in Christ and to be saved, then continues to live in deliberate, persistent,  unrepentant rebellion, simply does not believe in the real Jesus. How we live does not save us, and cannot save us, but it is evidence that we are saved.

© Rosemary Bardsley 2019