Perseverance of the Saints?

My first life experience with someone who held to the doctrine of “perseverance of the saints” was during the time I served in my first pastorate. I learned of a woman who struggled with addictions. She was taught by those who held strong Calvinist beliefs that if God chose her to be saved she would persevere over her addictions. Therefore, she rejected Biblical counseling as not relying on God’s will to deliver her. As her addictions persisted, she told her family that it must not be God’s will to be delivered so she must not be saved so why even try. She went on to live her life as an addict until she was involved in a horrific DWI crash. This led many in the church to wonder, “What does perseverance of the saints mean?”