Verified!!

Reader Jessica G. commented that the story shown was Moses striking the Rock from Numbers 20: 1-13.  So I looked up 17th century engravings of Moses Striking the Rock and found many engravings which all had the general composition of a grotto or large rock face/pile with a single stream coming out of it as he had a upheld arm with a stick in it and some grouping of people and animals ecstatic to the other side of the composition.  So I agree with Jessica that this one is Moses - mystery solved - and just WISH we could have seen the rest of the casket this piece must have come from!!

Moses Drawing Water From the Rock, from the series of etchings Biblical Scenes, after the frescoes by Raphael in the Vatican Loggia, 1607 (deYoung Museum, San Francisco) Acc. No. 1958.142.2.29

Moses Drawing Water from the Rock, Giovanni Battista Franco, 16th-17th century (deYoung Museum, San Francisco) Acc. No. 1963.30.36639