how can it be possible?
It says you are sealed until the day of redemption. Not till you stop believing, why are you adding to the word?
You think someone who has true faith in God would ever stop believing totally? Even faith of a mustard sead can move mountains. My faith my dwindle from time to time, but it will never cease.
You think it can, because your belief is in self and your good works. no wonder you think faith can fail. your faith is on the thing that is perishing, not in the one who is everlasting.
it does not lock you in for salvation. you do not lose you free will to accept God, you are not locked in to continue obeying Him even if you once did.
You cannot take "fallen from grace" out of this scripture not mater how much you twist, you cannot fall from something you were never on.
Galatians 5:4 (NKJV)
4 You have become estranged from Christ, you who attempt to be justified by law; you have fallen from grace.