This is The Quiet Book. Such an interesting book idea.
Here's a related idea.
Take a very short passage from scripture that includes "quiet" or "be still."
Ask your kids (any child old enough to be familiar with the word & fairly articulate), "What is 'quiet'?" or "What is 'be still'?" Then as a teacher or parent, think about how that understanding affects how the child understands the passage and how that affects how that child understands or knows God.