I heard two sisters reason on
Things that are past and things to come.
One Flesh was call'd, who had her eye
On worldly wealth and vanity;
The other Spirit, who did rear
Her thoughts unto a higher sphere.
"Sister," quoth Flesh, "what liv'st thou on
Nothing but Meditation?
Doth Contemplation feed thee so
Regardlessly to let earth go?
Can Speculation satisfy
Notion without Reality?
Dost dream of things beyond the Moon
And dost thou hope to dwell there soon?
Hast treasures there laid up in store
That all in th' world thou count'st but poor?
Art fancy-sick or turn'd a Sot
The questioning nature of the Flesh represents the struggle of puritan Christianity between worldly and spiritual satisfaction.  In many ways this is an internal struggle for Bradstreet as well.  Poetry as a genre is concerned romantically with worldly ideas such as dreaming, love, and aesthetic beauty which the Puritans would deem irrelevant compared to their hope for an afterlife.  But ironically throughout this poem the spiritual world can only be explained through physical poetic metaphor. For example “dream of things beyond the moon” or daydreaming is a secular idea of letting one’s mind wander creatively which would be problematic for the Puritan faith.  This struggle between Bradstreet’s life as a daydreaming poet and a spiritualist represents a potential debate about fitting into the history of poetry before her while remaining true to her own faith. 
 
 I believe that “Dost dream of things beyond the moon,” may also represent (also keeping the scientific knowledge of the time period) where one would literally believe heaven to be.  A belief that heaven was “up” beyond the physical plane.  I think this is corroborated by the following line, “And dost thou hope to dwell there soon?” I believe the Puritan concept of heaven to be literal, rather than to reach an enlightened place of creativity. 
 Here is a theatrical portrayal of Anne Bradstreet, I found on YouTube: 

Flesh and the Spirit The