Psalms 78:10

But what that is which he saith, "they have been turned back in the day of war," the following words do teach, wherein he hath most clearly explained this: "they have not kept," he saith, "the testament of God, and in His law they would not walk." Behold what is, "they have been turned back in the day of war:" they have not kept the testament of God. When they were bending and shooting bows, they did also utter the words of most forward promise, saying, "Whatsoever things the Lord our God hath spoken we will do, and we will hear." "They have been turned back in the day of war:" because the promise of obedience not hearing but temptation doth prove. But he whose spirit hath been trusted with God, keepeth hold on God, who is faithful, and "doth not suffer him to be tempted above that which he is able; but will make with the temptation a way of escape also," that he may be able to endure, and may not be turned back in the day of war. ...Therefore these men have been thus branded: "a generation," he saith, "which hath not directed their heart." It hath not been said, works, but heart. For when the heart is directed, the works are right; but when the heart is not directed, the works are not right, even though they seem to be right. And how the crooked generation hath not directed the heart, hath sufficiently been shown, when he saith, "and the spirit thereof hath not been trusted with God." For God is right: and therefore by cleaving to the right, as to an immutable rule, the heart of a man can be made right, which in itself was crooked. ...

"They did not keep the covenant of God, and in his law they were unwilling to walk, and they forgot his benefits." They rose up against him who regenerated them in baptism. "And his wonders which he showed them: before their fathers the wonders which he did." See the sense of the Scriptures, how from the sons of Ephraim it comes to past histories; so that it shows that what is written, "I will open my mouth in a parable, I will utter propositions from the beginning," was said parabolically.

They kept not the covenant of God,....

2Sa 19:41), it appears, in this place, that it had rather led the rest in cowardice than courage; and had incurred God's displeasure, because, diffident of His promise, though often heretofore fulfilled, it had failed as a leader to carry out the terms of the covenant, by not driving out the heathen (Ex 23:24;

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.