Since the OP was made in the Calvinist/Arminian debate forum, it needs to be stated that Calvinists do not believe in OSAS; they believe in the perseverance of the saints. There is a difference. OSAS is rooted in antinomianism. Say the prayer, get the Jesus insurance policy, and never question your salvation (no matter how ungodly your life is). Perseverance of the saints teaches that those who are truly saved are kept by the Holy Spirit and are in the on-going process of being conformed to the image of Christ. They may have serious bouts with sin, but the sanctifying work of the Holy Spirit is ever-present in their lives. As a rule, OSAS is satisfied with one's decision for Christ, whereas perseverance of the saints is concerned with growing in the Christian life and becoming more like Christ.