But...God doesn't see the "hugeness" of the giant, nor does he see the "smallness" of those stones in our hand. Instead, he sees the trust in our heart and the determination in our spirit! Through our natural eyes, the giant seems overwhelming, but in our spiritual sight he is brought down to realistic size!
David could have focuses on the size of those small stones in his hand, but he didn't. Instead, he recounted the many times God stood by him when faced with other "giants" that some would have seen just as frightful as this one standing before him presently. He had faced the lions and bears in the open fields. He had endured the cold nights while tending the flocks, ever vigilant to listen for the creeping advances of the enemy who was out to steal, kill, and scatter his father's flocks. The club in his hand, the stones in his pouch, the sling in his hand - it didn't matter what his weapon of the moment would be - what mattered was the "weapon" in his heart and his mind!
We focus on the vastness of the enemy's resources and ability, hearing his taunts and listening to his jeers. David focused on the greatness of God's grace and the strength of his powerful name. The "smallness" of the stones in our hands matter not - it is the "massiveness" of God's power ignited with the declaring of his name that makes even the smallest of weapons in our hands the greatest of weapons with which to slay the giants in our path! Just sayin!