The Treasure of the kingdom of heaven is that which is old and new at the same time. The medieval Christian Scholars argued that the mention of the old and the new treasure in Matthew 13:52 referred to the Old and New Testaments of the bible. But there is much more than that. Jesus is not telling these teachers in training that they have only the treasures of the old covenants and the new covenant with Jesus to share to a fallen world.

They have a truly new message that is truly old.

All of the covenants of God in the Old Testament point to the final New Covenant in Jesus.