Final answer:
In the second stanza, the speaker mentions borders that divide people while they are alive. When humans die, these differences and borders cease to exist. The poem conveys that the borders we use to separate ourselves are artificial and unnecessary.
Step-by-step explanation:
In the second stanza of the poem, the speaker mentions several borders that divide people while they are still alive. These include geographical borders (oceans, mountains), religious borders (creeds, sects), and social borders (castes, classes). According to the speaker, when humans die, all the differences and borders we perceived when we were alive cease to exist. Death erases the divisions that we create in life. The message (theme) that the author conveys about the borders we use to separate ourselves is that they are artificial and unnecessary, as death ultimately unifies all humans.