The complete text translates into English as follows:
"The sage is as humble as [a] valley,
The Benevolent is as quiet as [a] mountain."
From Janie's email:
賢者虛懷若谷仁人習靜如山A sage’s mind tends to be as humble as [a] valley.A benevolent [person]’s heart learns to be as quiet as [a] mountain.甲午春 薛公惠書2014 SpringWritten by Michael Shiue