This doctrine teaches that salvation can never be lost, despite the lifestyle you lead or the actions you take–even if it means denying Jesus and turning your back on Him. This view is based on Romans 8 and John 10 which in summary state that nothing can separate us from the love of God, and that Jesus’ sheep have eternal life and no one can pluck them out of His hand.
This theological stance is very controversial amongst Christians. There are well-respected theologians and pastors on both sides of this issue. I also have dear friends who differ from me on this topic.