Why was the moon so important to Ishmael?

In Chapter One, an old man encourages Beah that they should “be like the moon”. When Ishmael asks his grandmother what this means, she explains that even though people complain when the sun shines too brightly, no one is annoyed by the brightness of the moon. Good things happen when the moon is full and its light is at its greatest. Beah remembers his own experiences as a six-year-old boy, lying on the ground at night looking up at the moon. He remembers the various images he saw in the moon, and in recalling this pleasant memory from his childhood, he is encouraged.