I am a secure believer in Jesus Christ and believe I have 100% assurance in Christ and know that I have been redeemed and have an eternal reward. But what if tomorrow I choose to forsake Christ, cease believing in Him, and even become an agnostic or atheist? What then?
This is a real question for me: I have a brother-in-law who was a believer living victoriously and clearly for the Lord, but now is an avowed atheist. Is he saved? Most people who believe in OSAS tell me that my brother-in-law must not have been a Christian.
It seems to me that this is judging my brother-in-law by his works. His works no longer match up so that proves he could never have been a believer.
Thus I assume that OSAS supporters would say the same of me if I became an avowed atheist. They would tell me you could never have been really born again.
I know that today I am believing in Jesus Christ as my Saviour, Redeemer, and Lord, and on that basis I have 100% assurance that I am saved. If I adopted belief in OSAS, I would need to be sure my works kept matching up, or I would be told that I was never really born again.