This story is based on Numbers 20.  This is a famous incident in which God wants Moses to “speak” to a rock so that Israel will be supplied with water.  Instead, Moses strikes the rock.  Both Moses and Aaron (his brother) were involved.  And, both incurred God’s anger and punishment.  The punishment was that neither would be allowed to enter Canaan, the Promised Land.  As it turns out, though, it seems there was another reason that Moses got into trouble.  This time, at least, Israel did nothing wrong.  But Moses did.  He accused Israel of being rebellious when he was the one being rebellious.