Charles H. Spurgeon on Psalms 78:10

They kept not the covenant of God. Vows and promises were broken, idols were set up, and the living God was forsaken. They were brought out of Egypt in order to be a people separated unto the Lord, but they fell into the sins of other nations, and did not maintain a pure testimony for the one only true God. And refused to walk in his law. They gave way to fornication, and idolatry, and other violations of the decalogue, and were often in a state of rebellion against the benign theocracy under which they lived. They had pledged themselves at Sinai to keep the law, and then they wilfully disobeyed it, and so became covenant breakers.