Their nation was facing or living in exile.  It was hard to understand, because the land was a major part of the covenant that had been established with Abraham.  Joshua had led them through battles to secure the land.  Now - with Israel first and Judah to follow - they were exiled from their land.  How were they to understand what had happened?  How would this experience affirm or alter their understand of God.  Hosea was given a harsh command - marry someone who is unfaithful so you can know what it is like to love someone (a people) who is/are rebellious and unfaithful.