At this point the tone of the Voluspa takes a shift. The prophetess start's to reveal Odin's secrets. In the first section she tells him of the past, in this short middle section of 4 verses she tells him of the present, of secret things. This is to establish her credibility, for the last section where she tells him of the future.
Voluspa - Norse Mythology Book - Verse 27
“I know of the horn | of Heimdall, hidden
Under the high-reaching | holy tree;
On it there pours | from Valfather’s pledge
A mighty stream: | would you know yet more?”