Deuteronomy 4:14-28
Being in the centre of the surrounding nations Israel was to stand out by her wisdom and her understanding (Deuteronomy 4:6). This wisdom and understanding consisted of knowing the only true God, listening to Him and being in submission to Him. Those nations bordering Israel were worshipping idols. As a result they "became vain in their imagination and their foolish heart was darkened; professing themselves to be wise, they became fools, and changed the glory of the incorruptible God into an image like to corruptible man, and to birds, and four-footed beasts and creeping things" (Romans 1:21-23). It is that terrible sin of idolatry that Israel is to guard against here. Nowadays, except in pagan countries, we hardly come across this gross form of idolatry. However the New Testament gives this name to other sins: greed for example, and warns us solemnly that no idolater will inherit the kingdom of God (Ephesians 5:5; 1 Corinthians 6:9-10).
Whilst warning Israel, God does not hide from her what must come to pass: the people will corrupt themselves, they will serve pagan gods. The Word of God never flatters nor deludes us as to what our natural hearts are capable of doing.