While there is a common theme of Ambition as a driving force in Langston Hughes's "Dreams" and Shakespeare's Macbeth, the elements of character and the phantasmagoric in the dreams of Macbeth transcend what is implied in Hughes's poem. For, one can only assume that the dreams to which the poet urges the reader to "hold fast" are worthy dreams and not such murderous, treacherous ones as the later ones of Lady Macbeth and Macbeth himself.
This truth notwithstanding, given the assignment, it may be contended that the end result of not reaching one's worthy dreams in both literary works is the "barren field." So, focusing upon Macbeth's original dream of being Thane of Cawdor as a worthy one, perhaps the best direction of the persuasive essay may be in using the last lines of "Dreams" as holding the key to the thesis of the essay since when he conspires with the preternatural world, Macbeth's decent dream transforms into a treacherous one; in other words, his worthy dream "goes" just as the dreams of the poem "go,"
... when dreams go
Life is a barren field
Frozen with snow.
Remembering the words of Robert Frost's poem "Fire and Ice,"--that Ice is as deadly as Fire--the writer can use the connotation of ice/snow as destructive force. The argument for Macbeth, then, can be that Macbeth's joining with the phantasmorgoric takes him down a bloody path which destroys his worthy dreams, leading to the much the same end of dreams of which Hughes writes as "a barren field/Frozen with snow."