הבט נא השמימה וספור הכוכבים… כה יהיה זרעך (לך לך טו:ה)

The stars may seem small in our eyes, but they’re huge.  The pasuk implies that the Yidden are compared to the stars; they may appear small in this world, but they’re considered significant in Heaven.

By Hashem comparing the Yidden to the stars, He promised them that despite being in the darkness of galus-exile, they will always illuminate the world like the stars shining during the dark night.