The slash is sometimes used to represent a conflict or connection between two things. As explained here, the en dash can perform the same role. Up above the world so high, like a diamond in the sky.
Poetry likes to employ slashes to separate lines of prose. The one inarguably acceptable use of the slash in formal writing pertains to poetry.
When the quote is this short, you use slashes to indicate where the line breaks are. The slash is used to separate the numerator from the denominator in fractions. An explanation of what a forward slash means in a text depends on the context. The slash sometimes serves as shorthand for per.
The slash, with one space on either side, indicates a line break. Note that you add a spaces around the slash. Be the best writer in the office. For an in-text citation, the style is much the same as mla.