Meaning
A "heart of stone" denotes great insensibility (1Sam 25:37).
Stones were set up to commemorate remarkable events, as by Jacob at Bethel (Gen 28:18), at Padan-aram (35:4), and on the occasion of parting with Laban (31:45-47); by Joshua at the place on the banks of the Jordan where the people first "lodged" after crossing the river (Josh 6:8), and also in "the midst of Jordan," where he erected another set of twelve stones (4:1-9); and by Samuel at "Ebenezer" (1Sam 7:12).