“You saw the suffering of our ancestors in Egypt; you heard their cry at the Red Sea. You sent signs and wonders against Pharaoh, against all his officials and all the people of his land, for you knew how arrogantly the Egyptians treated them. You made a name for yourself, which remains to this day.” Nehemiah 9:9-10

            If they remember what God did, they will know what God can do.  Looking back gives hope when looking forward and reminds the people of what they need to do (remain obedient).