At this point the prophetess is challenging Odin. She's proved her knowledge of the past, what is it that Odin really came for?

Voluspa - Norse Mythology Book - Verse 28

“Alone I sat | when the Old One sought me,

The terror of gods, | and gazed in mine eyes:

“What hast thou to ask? | why comest thou hither?

Othin, I know | where thine eye is hidden.”

Bellows Translation