What is the difference in the art works of Michelangelo's Pieta and David

David is a sculpture portraying one individual, whereas, Pieta depicts Mary and Jesus. Michaelangelo is also a nude, whereas, Mary and Jesus are clothed in the Pieta. There are also slight differences in the mood, the Pieta is sad and melancholic, a mother holding her crucified son. David, on the other hand, is determined and preparing for battle.