83. It is indeed the height of folly, not to say of madness, for a person who deliberately takes pleasure in destructive sins to seek salvation through the prayers of the just and to ask them to obtain forgiveness for what he actively glories in, denied as he is by his own free choice. If he really hates what is evil, he should not ask for the prayers of a just man and then allow them to become void and ineffectual; but he should make them active and strong, so that winged with his own virtues they may reach Him who has power to grant forgiveness for sins.
The prayers of others cannot overtake our own will. This is different than prayers that help free us from passions that rule us and which bypass our will and the one praying may not be able to see or know the difference. But God will not contravene our will. Our ability to choose is a part of the good creation he loves. We can ask for prayer as much as we want, but until we set our will, however feebly, against the destructive sins for which we ask prayer, those prayers will be ineffective.