IS ALL SCRIPTURE PROFITABLE?

II Timothy 3:16  All scripture is given by inspiration of God, and is profitable for doctrine, for reproof, for correction, for instruction in righteousness: (KJV) Hebrews 7:18  For there is verily a disannulling of the commandment going before for the weakness and unprofitableness thereof. (KJV)

Only a good understanding of the old and new covenants can bring one to fully understand what is being said here.  But to summarize, all scripture is profitable, but 'profitable' is a relative term.  The Old Testament Levitical laws (which are being referred to in the Hebrews passage) serve their purpose, but will not bring about the perfection that only Jesus can bring.  So in relation to Jesus, the Levitical laws are unprofitable. But in relation to man without Jesus, they are very profitable.  Not a contradiction.