Illustrate a holy and sacred scene that showcases the biblical event described in Exodus 20:18-19. The setting is Mount Sinai, dominated by divine presence and a thunderous voice resonating mightily, the event instilling awe and shaking nations far and wide. This scene should be created using watercolor techniques, with an emphasis on soft color transitions and fluid strokes. The imagery should be respectful and evoke a strong sense of devotion towards Christianity, embodying a spiritual and profound atmosphere.