This chapter reports on the behavior of the people placed in Israel after Israel's conquest and deportation by Assyria between 722-720 BC. These people, who became known as the Samaritans, feared the Lord but worshipped their own gods. They were afraid of God, but they did not really change their way of life. Thus, they developed a syncretic religious system, a blending of the truth of God and outright paganism. The Jews of Christ's day clearly recognized this putrid blend and despised the Samaritans for it.
What is so interesting is that, by verse 35, it is clear God is no longer addressing Himself to the Samaritans, but to Israel:
… [T]he LORD had made a covenant and charged [Israel], saying: "You shall not fear other gods, nor bow down to them nor serve them nor sacrifice to them; but the LORD, who brought you up from the land of Egypt with great power and an outstretched arm, Him you shall fear, Him you shall worship, and to Him you shall offer sacrifice. And the statutes, the ordinances, the law, and the commandment which He wrote for you, you shall be careful to observe forever; you shall not fear other gods. And the covenant that I have made with you, you shall not forget, nor shall you fear other gods. (II Kings 17:35-38)
In other words, God is saying that He was driven to defeat and scatter Israel because they were guilty of exactly the same sin as the Samaritans! They too had blended the worship of the true God with outright paganism, utterly corrupting the relationship He had established with them.
It is urgent that we understand what is involved here because it reveals the cause of God's anger that led to Israel's defeat and scattering. We must understand that our god is not what we say we worship but what we serve. Our god is what we give our lives over to.
Theoretically, the Israelites did not believe in idols, but in reality, they did. They believed in a Creator God, but they worshipped Him at the shrines they erected to the Baals. While they gave lip service to the Creator, they adopted most of the Canaanitish religion with its lewd immorality, and in actual practice, patterned their life after it. In daily life, they conformed to and reflected the Babylonish system just as Israel does today. This is exactly what God warns us to flee, and the only way to come out of it is by developing and maturing in our relationship with God.