The helmet is worn by a soldier to protect their head. In the same way, a Christian protects their "head" with the knowledge of salvation.
If a soldier is injured in most other parts of their body, they can survive. But if they are shot or stabbed in the head, survival is unlikely. And in the same way, a Christian needs to protect their salvation by faith and knowledge so that they are not lost.
Listen to this podcast now to find out more.