In chapter 3, God reassures that he will forgive Israel. They will spend time separated from God’s protection, but he will buy them back. Chapter 4 begins a list of the things Israel was doing that God saw as spiritual adultery.
Even after a time of wandering from God, he is faithful. Many experience that today. We often hear stories of those raised knowing God and then rebelling against him. Later they return to God and see those years of rebellion as wasted.