A.B. Simpson emphasizes the power of being filled with the Holy Spirit, which enables believers to be 'sin proof' and protected from the attacks of the enemy. He illustrates that just as fireproof and waterproof materials resist harm, a life empowered by the Spirit can repel sin and evil influences. Simpson encourages Christians to cultivate a deep relationship with Jesus, allowing His presence to shield them from spiritual dangers and to walk confidently even in challenging circumstances. He reminds us that through Christ, we can maintain our purity and resist temptation, as we are nourished by His life.

We know what it is to be fireproof or to be waterproof. But it is a greater thing to be sin proof. it is possible to be so filled with the Spirit of Jesus that all the shafts of the enemy glance off our heavenly armor. It is possible to so know the presence of Jesus that all the burrs and thistles which grow on the wayside fail to stick to our heavenly robes. All the noxious vapors of the pit disappear before the warm breath of the Holy Ghost, and we walk with a charmed life even through the valley of the shadow of death. The red-hot iron repels the water that touches it and the fingers that would toy with it. If we have been set aflame by the Holy Spirit, Satan will keep his fingers off us, and the cold water that he pours over us will roll off and leave us unharmed. We know that whosoever is born of God sinneth not; but he that is begotten of God keepeth himself, and that wicked one toucheth him not (1 John 5:18). Before going into a malarial region, it is well to fortify the system with nourishing food. So we should be fed and filled daily by the life of Christ in such a way that evil cannot invade our lives.