The Heresy of Once Saved Always Saved

"Don’t you realize that in a race everyone runs, but only one person gets the prize? So run to win! All athletes are disciplined in their training. They do it to win a prize that will fade away, but we do it for an eternal prize. So I run with purpose in every step. I am not just shadowboxing. I discipline my body like an athlete, training it to do what it should. Otherwise, I fear that after preaching to others I myself might be disqualified."
1 CORINTHIANS 9:24-27 NLT