«فَبُوحِي بِالسِّرِّ الْمُبْهَمِ»
Then disclose the hidden secret.
Būḥī is a feminine singular command from the root b-w-ḥ, “to disclose.” Mubham refers to something still obscure. The narrator’s request is more than a casual question: he suspects that the poems and the elder’s hidden identity belong to a larger pattern.