Israel and Judah have forsaken the Lord...
Verse 3
The Lord says that "Israel hath cast off the thing that is good: the enemy shall pursue him". Israel declined to follow and worship the Lord, and therefore they lost his protection.
Verses 8-9
Again, Israel's stubbornness is described using a stubborn animal...a "wild ass". Israel did not want to do what the Lord wanted them to do, instead they chose their own way and followed after their own hearts.
The "lovers" described in this verse refer to Ephraim's many attempts to find friends and security through political alliances, instead of doing this through obedience to God.
Verse 13
The first part of this verse indicates that the Lord did not accept their sacrifices. The reason he didn't accept them is because they were only the shell of the sacrifice, or the physical act of completing the sacrifice. Their hearts were not in it and their spirits were not in it. This applies to the offerers and the priests.
The Lord also indicates that they will return to bondage in Egypt. Egypt is used as a general term for bondage. Assyria would be the actual nation that would be involved this time.