18 “When he sits on the throne as king, he must copy for himself this body of instruction on a scroll in the presence of the Levitical priests. — Deut. 17:18 NLT

God knew that once the Israelis had settled in the land and become comfortable, that they would look around and desire what the other nations had.  They would grow tired of the judges and desire a king so they could be like the nations around them.  God had given Moses several guidelines for the king once he had been anointed.  Most of those were what not to do and had to do with position and possessions.  But the positive thing he was required to do was to copy the whole body of the instructions on a scroll.  To be sure, he did this himself, he had to do it in the presence of the priests.  Then he must keep it with him and read it every day.  One would think that this would have been sufficient to keep the kings in line with what God expected.  But that was not the case.  The majority of the kings were not godly and worshiped other gods.  The lesson that we can learn from this is that head knowledge is useless unless it affects the heart.  The devil knows the Bible but it doesn’t keep him from being the devil.  Just reading the Bible on a daily basis will not change us.  A heart change only takes place when we fully believe that Jesus, the Son of God, died for our sins.  Just saying the words does not make it happen.  We need confession and we need believing.