‘ And Joshua said to all the people, “Behold, this stone shall be a witness against us, for it has heard all the words of YHWH which he spoke to us. It shall therefore be a witness to you, lest you deny your God.” '
A stone for Jacob (Genesis 31:45) and a heap of stones for his brothers-in-law (Genesis 31:46) stood as a witness between Jacob and Laban, each stone seemingly representing a tribal leader. This stone therefore probably represented Israel. It had ‘heard' all that was said and stood there as a witness to it and to Israel's responsibility to keep the covenant. The idea that somehow stones had something to testify about (even though they never did) lies behind the words of Jesus in Luke 19:40.