Final answer:
The phrase "The moon’s metal buckle" sets a tone of awe and reverence, comparing the moon's importance to a buckle that holds together the night sky.
Step-by-step explanation:
The line that establishes a tone of awe and reverence is "The moon’s metal buckle." This phrase evokes a sense of majesty and admiration, suggesting the moon's grandeur as it shines in the sky. The use of "metal buckle" implies that the moon holds together the night sky akin to a buckle securing a garment, which adds to the tone of reverence towards this celestial body.