en_tn/2sa/15/35.md

Will you not have the priests Zadok and Abiathar with you?

David asks this rhetorical question to tell Hushai that he will not be alone. This can be written as a statement. Alternate translation: "Zadok and Abiathar the priests will be there to help you." (See: rc://en/ta/man/jit/figs-rquestion)

whatever you hear

This is a generalization. It means all of the important and insightful things that he hears, not every single word he hears. (See: rc://en/ta/man/jit/figs-hyperbole)