“Then Joshua said, “You are witnesses against yourselves that you have chosen to serve the Lord.” “Yes, we are witnesses,” they replied. “See!” he said to all the people. “This stone will be a witness against us. It has heard all the words the Lord has said to us. It will be a witness against you if you are untrue to your God.”” – Joshua 24:22, 27 NIV

I find it interesting that he makes effort to have even rocks hold them accountable. We should make every effort to keep ourselves accountable as well to do right by God and his commands to us even if that means using a stone to hold us accountable.