10 After this do we not feel shame, and hide our faces, at seeing that righteous man for twenty years persevering and not desisting; we ourselves after a first or second petition often fainting and indignant? And yet he indeed had in large measure liberty of speech towards God, and all the same he felt no discontent at the delay of the giving, but remained patient, whereas we, laden with countless sins, living with an evil conscience, displaying no good will towards the Master; if we are not heard before having spoken, are bewildered, impatiently recoil, desist from asking— on this account we always retire with empty hands.
Who has for twenty years besought God for one thing, as this righteous man did? Or rather who for twenty months only? Yesterday I was saying that they are many who pray with slackness, and yawning, and stretching themselves, and continually shifting their attitude, and indulging in every carelessness in their prayers— but today I have found also another damage attaching itself to their prayers more destructive than that one. For many, throwing themselves prostrate, and striking the ground with their forehead, and pouring forth hot tears, and groaning bitterly from the heart and stretching out their hands, and displaying much earnestness, employ this warmth and forwardness against their own salvation.
For it is not on behalf of their own sins that they beseech God; nor are they asking forgiveness of the offenses committed by them; but they are exerting this earnestness against their enemies entirely, doing just the same thing as if one, after whetting his sword, were not to use the weapon against his enemies, but to thrust it through his own throat. So these also use their prayers not for the remission of their own sins, but about revenge on their enemies; which is to thrust the sword against themselves.
This too the wicked one has devised, in order that on all sides we may destroy ourselves, both through slackness and through earnestness. For the one class by their carelessness in their prayers exasperate God, by displaying contempt through their slackness; and the others, when they display earnestness, display the earnestness on the other hand against their own salvation. “A certain person,” he (the devil) says, “is slack: that is sufficient for me with a view to his obtaining nothing; this man is earnest and thoroughly aroused; what then must be done to accomplish the same result?
I cannot slacken his earnestness, nor throw him into carelessness; I will contrive his destruction in the other way. How so? I will manage that he use his earnestness for transgressing the law:” (for the praying against one's personal enemies is a transgression of law). “He shall depart therefore not only having gained nothing by his earnestness, but also having endured the hurt which is greater than that caused through slackness.” Such as these are the injuries of the devil: the one sort he destroys through their remissness; and the other through their earnestness itself, when it is shown not according to God's laws.
Source: Homily Against Publishing the Errors of the Brethren (New Advent)