But what that is which he says, "they have been turned back in the day of war," the following words do teach, wherein he has most clearly explained this: "they have not kept," he says, "the testament of God, and in His law they would not walk" [Psalm 78:10]. 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 has spoken we will do, and we will hear." [Exodus 19:8] "They have been turned back in the day of war:" because the promise of obedience not hearing but temptation does prove. But he whose spirit has been trusted with God, keeps hold on God, who is faithful, and "does not suffer him to be tempted above that which he is able; but will make with the temptation a way of escape also," [1 Corinthians 10:13] 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 says, "which has not directed their heart." It has 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 has not directed the heart, has sufficiently been shown, when he says, "and the spirit thereof has 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....
[AD 430] Augustine of Hippo on Psalms 78:10