The numbering of Emily Dickinson's poems has not been identified as concrete, based upon the times they were found and published. Dickinson did not title her poetry; instead, her poems were assigned numbers based upon assumptions made by those in charge of publishing. That said, "Because I could not stop for Death" is overwhelmingly denoted as poem 290. (Some critics denounce this number and define "Of Bronze--and Blaze" as poem 290.) Therefore, to reside with the majority, this is the poem which will be explained.
In "Because I could not stop for Death," the speaker denotes the business of life as far more calling than death itself. Death has been personified in the poem (which means that it has been given human qualities--like patience, kindness, and civility. Understanding the life of a busy human, Death decides that he (gender denoted by the speaker) will insure that time is made. After getting into Death's carriage, the speaker takes a journey. This journey allows the speaker to see life from childhood through the grave.
We passed the school, where children strove...
We paused before a house that seemed
A swelling of the ground;
Here, death keeps the idea that one's life flashes before them upon death (giving the visit from childhood-an early memory- to the final "memory"--given that the soul lives on past death).
In the end, the poem speaks to the fact that Death will come for all no matter what. Regardless of one's busy life, death can (and will) come at any time. One cannot simply avoid death by being busy. Instead, Death has its own schedule to keep.