OSAS is a heretical concept created by Jews 2000 yrs ago, to try to subvert the understanding of God's Grace, so that a believer would be deceived.
What this teaching is designed to do,
according to JUDE..... is create the false concept that God's Grace is.. "Licentiousness"...or freedom to live like the devil.
So, once this becomes your belief, then you will find it almost impossible to ever understand God's Grace as "the GIFT of Salvation", and "The Gift of righteousness".
So, now that your faith is subverted your Christianity is the same.
See.... this idea of "license to sin", is designed to corrupt your understanding of God's Gift of Salvation, so that you will always try to keep yourself saved, and you'll always feel that you can lose your salvation.
And what is that?
That is broken faith that has disconnected from God's Grace.
You are now "fallen from Grace" .. as Paul explains..
And when your faith is ruined, then your Christianity has become your own idea of self righteousness to try to earn your way into heaven based on SELF EFFORT.