David stooped down to pick up five stones from the wadi, and he placed one in his slingshot. David is charity, his slingshot with its direction is hope, and the only way is faith, which is the stone slung. The other four stones which he takes with him are the four cardinal virtues: justice, temperance, fortitude, and prudence. It is charity which directs, and hope which gives aim; faith is what is slung, and all the other virtues can be slung, too, and must never be left in the wadi. They must be carried and used if necessary. But here David is and takes first love, hope, and faith, because these virtues are nearer to God.
David refused to take the armour King Saul offered him. “I cannot walk with these,” he said. The armour represents the “virtues” of the world and any attachment that would weigh us down. They may be strong. But if the helmet has not the humility of Christ, and if the coat of mail has not obedience to providence, then it is all lost. The weakness of human means is the source of God’s strength. Refusing the armour is what lets us stoop down and walk to the wadi to pick up the humble gifts of true virtue. It is David, the divine love of charity, who said no to the armour of King Saul, who represents the ways, decisions, “prudence”, and operations of the world.
Goliath is tumbled with one small stone. Goliath represents all that must be conquered in this life: the world, the flesh, the devil.
When first the small stone knocks out the aggressor, David runs over to Goliath, takes his own sword, and cuts his neck. The small stone is the divine dart of love thrown into our soul in contemplation; it is the simplicity, increasingly tender, of contemplative love, gazing on the Beloved through life’s moments. But contemplation runs into action and enlivens it all, for, holding all the stones (virtues) in its sack, the slingshot in its hand, and following its hope to its course, contemplation is the life blood of action in this world. The sword is action. David, charity deepened in contemplation, takes the sword and slices off the enemy’s own head.
When all is over, Jonathan is in wonder and is bound to David. They make a covenant. Now, Jonathan is another soul. Jonathan is our neighbour. David and Jonathan are neighbours, bound tightly together because of the suffering of divine things, because of the virtues, and because of the ever-growing interrelation of action and contemplation.
And when David takes the signs of Jonathan’s love, he goes out and becomes successful wherever Saul, who represent the legitimate demands of this world, sends him. This is the divine providence at work for and making demands of those whose very action is taken into their contemplation in this world. God works within our neighbours. Action and contemplation grow into greater and greater union also.
This is my own spiritual-moral interpretation. I don’t see any reason to throw doubt on it, though. The truths of Christian contemplation are found in the Scriptures in various ways.