[chromeaway]

In the ancient near east people did not refer to literary works by means of a dedicated title, but by the first line of the composition, which is taken as an indication of origins in an oral tradition, esp. for the earliest works that were written down. When large portions of text have been committed to memory, reciting the first sentence is often enough to trigger a flow, a small but useful "technique" applied by e.g. hiphop lyricists.

[kuu]

This is still done today even if not with the same intention. When we don't remember a name of a song we repeat part of it "do you know this song? the one that says X..." It's natural