I think the reason The Book of Songs is precisely not categorized as an “epic” is because it deliberately goes against the need for “epic unity”. Instead of conforming to the standards of an epic poem, the anthology achieves the same purpose, by “attempting to embrace every aspect of its world” (foreword, xvi). Furthermore, the definitive aim was to “create relations” between not just different social groups, but also specific relations such as the rulers-commoners, children-parents as well to ultimately “bind them together” (foreword, xvi).
In Cocklebur (pg.7), this clear demarcation between husband and wife is demonstrated by the distinct social roles they fulfill as well as the sheer physical distance between them. The first stanza, the woman is speaking, “sighing for the man [she] loves,” distracted and lonely. In the three remaining stanzas, the man yearns to see his lover; not only is he physically exhausted, but he is mentally pained and in anguish and all he can do is drink from his cup “to still [my] heart’s yearning/pain.” Even though they are miles and miles apart from each other, there is a subtle beauty to the poem, laced with suffering and desire. In a way, the two lovers are united, thinking about one another and this poem is the vessel in which the reader feels the two can be bound together through song.
The Book of Songs does not just touch on the relationship between a man and a woman. There are examples of a king and a commoner, a woman and her parents, a lady and a lord. This text is not at all exclusive and instead embraces all facets of society, creating a myriad of stories embedded in one great text.