If I choose to put a tattoo on my arm, that would involve a one time act on my part. Yet the tattoo would remain with me indefinitely. I don’t have to maintain a fondness for tattoos to ensure that the tattoo remains on my arm. In fact may change my mind theminute I receive it. But that does not change the fact that I have a tattoo on my arm. My request for the tattoo and the tattoo itself are two entirely different things. I received it by asking and paying for it. But asking for my money back and changing my mind will not undo what is done.
Forgiveness or salvation is applied at the moment of faith. It is not the same things as faith and its permanence is not contigent on the permanence of one’s faith.
From the book "Eternal Security"