II. Consider next, the defence: 'the shield of faith.'
Now, the Old Testament says things like this: 'Fear not, Abraham; I am thy Shield.' The psalmist invoked God, in a rapturous exuberance of adoring invocations, as his fortress, and his buckler, and the horn of his salvation, and his high tower. The same psalm says, 'The Lord is a shield to all them that put their trust in Him'; and the Book of Proverbs, which is not given to quoting psalms, quotes that verse. Another psalm says, 'The Lord God is a sun and shield.'
And then Paul comes speaking of 'the shield of _faith_.' What has become of the other one? The answer is plain enough. My faith is nothing except for what it puts in front of me, and it is God who is truly my shield; my faith is only called a shield, because it brings me behind the bosses of the Almighty's buckler, against which no man can run a tilt, or into which no man can strike his lance, nor any devil either. God is a defence; and my trust, which is nothing in itself, is everything because of that with which it brings me into connection. Faith is the condition, and the only condition, of God's power flowing into me, and working in me. And when that power flows into me, and works in me, then I can laugh at the fiery darts, because 'greater is He that is with us than all they that are with them.'
So all the glorification which the New Testament pours out upon the act of faith properly belongs, not to the act itself, but to that with which the act brings us into connection. Wherefore, in the first Epistle of John, the Apostle, who recorded Christ's saying, 'Be of good cheer; I have overcome the world,' translates it into, 'This is the victory that overcometh the world'--_not_, our Christ, but--'even our faith.' And it overcomes because it binds us in deep, vital union with Him who has overcome; and then all His conquering power comes into us.
That is the explanation and vindication of the turn which Paul gives to the Old Testament metaphor here, when he makes our shield to be faith. Suppose a man was exercising trust in one that was unworthy of it, would that trust defend him from anything? Suppose you were in peril of some great pecuniary loss, and were saying to yourself, 'Oh! I do not care. So-and-so has guaranteed me against any loss, and I trust to him,' and suppose he was a bankrupt, what would be the good of your trust? It would not bring the money back into your pocket. Suppose a man is leaning upon a rotten support; the harder he leans the sooner it will crumble. So there is no defence in the act of trust except what comes into it from the object of trust; and my faith is a shield only because it grasps the God who is the shield.
But, then, there is another side to that thought. My faith will quench, as nothing else will, these sudden impulses of fiery desires, because my faith brings me into the conscious presence of God, and of the unseen realities where He dwells. How can a man sin when God's eye is felt to be upon him? Suppose conspirators plotting some dark deed in a corner, shrouded by the night, as they think; and suppose, all at once, the day were to blaze in upon them, they would scatter, and drop their designs. Faith draws back the curtain which screens off that unseen world from so many of us, and lets in the light that shines down from above and shows us that we are compassed about by a cloud of witnesses, and the Captain of our Salvation in the midst of them. Then the fiery darts fizzle out, and the points drop off them. No temptation continues to flame when we see God.