The statue of David (photo above) has three interesting points of study. It references the 3 moments: past, present, and future. It is a self-portrait of Bernini himself; and it showcases varying textures and qualities carved out of the one substance: marble.
To begin with the three moments, in the past, David had taken off his armor. The observer can see it laying behind him. The future is the felling of Goliath, which the purpose behind the present action. In the statue’s present, David is readying to throw the stone at Goliath. This is the moment in the story of David and Goliath which contains the most tension. This tension can be seen in David’s expression and in the tight coiled posture of his body. Everything is poised for the attack.
But Bernini is not only telling David’s story, he is telling his own. Bernini was lauded as the best in Rome during his time and that meant that everyone was watching him, waiting for him to make a mistake. This is the tension in Bernini as he sculpts the rock. David’s rock and the rock Bernini sculpts are both weapons wielded against those who do not believe in them.
The third point of study in Bernini’s David are the varying textures sculpted into the work. The hair is different from the skin. The skin is different from the bag at his side. All are different from the pile of armor in the background. Some surfaces are polished, some unpolished. Some aspects have been given a shaggy or a rough texture, others smooth. Out of one block of marble, Bernini has sculpted many things, each with its own fitting texture and posture. David, with one small rock, knocked a giant to the ground.
Resource: our Virtual Pilgrimage to the Villa Borghese part 2 (watch on YouTube here)