"All this is because of Jacob's transgression, because of the sins of the people of Israel. What is Jacob's transgression? Is it not Samaria? What is Judah's high place? Is it not Jerusalem?" NIV translation
The charges against the northern and southern kingdoms was that they set up images to be equal to God. In the north, it was at Samaria which was not even the prescribed place of worship (Jerusalem). In the south, they set the idols up in the holy city of Jerusalem. It was not that they totally abandoned God but the fact was that they tried to trust in both God and their idols. God is a jealous God and will not tolerate anyone or anything being elevated to the place that is set aside for Him as Creator of all things.
It is easy for us to say that we do not do this type of thing but is that true? Do you put your trust in your family, your job, your pastor, or your retirement account? Are we like Judah where we do not replace God but we simply split our trust between Jesus and our own efforts? Real faith (trust) is only faith when it's all you have!