Which lines in this excerpt from the poem "a grain of sand" by frances ellen watkins harper indicates its subject?
(do you see this grain of sand)
lying loosely in my hand?
do you know to me it brought
(just a simple loving thought? )
when one gazes night by night
(on the glorious stars of light,)
(oh how little seems the span)

The lines in this excerpt from the poem A Grain of Sand by Frances Ellen Watkins Harper that indicate its subject for me are:

(Do you see this grain of sand)

(Oh how little seems the span)

In this poem, the narrator is comparing a grain of sand with the significance of human life. She uses the grain of sand to show how small can a part of the beach be, how it is "lying loosely" in her hand and how us, individuals, are like a grain of sand in the Universe, "how little seems the span".  

The idea of the whole poem is to show how small and insignificant can a part of everything seem to be.

honestly this is the biggest mood ever, i couldn't relate to this more

explanation: