The commentary on this poetic witness considers two dimensions: the praised person's traces and reports are visible and audible, and the nonmention of objects keeps attention on the act of seeing and hearing itself.
Neither clause need be construed as a literal universal assertion about every occurrence of seeing or hearing. The rhetorical context of praise and indirection produces the sense that the subject's excellence cannot easily remain concealed.
Methodologically, distinguish the explicit verbal form from the rhetorical implication, then explain how the latter arises from the former.