When someone asked a 10th-century Byzantine saint how to pray, he responded:
“The prayer is simple: Lord Jesus Christ Son of God have mercy on me a sinner. The question is how you say it. Imagine a person accused of a crime. It doesn’t matter whether the accusation is fair or not — he is sentenced to death. All his appeals were turned down, and the verdict was final. He is being led from the prison to the central city square, passing the king’s palace on his way to the scaffold. He seizes this last chance to ask the king to have mercy on him. To do so, he has to shout “Lord have mercy!” so loud as to make the king hear his outcry and help him. That is how we should cry out “Lord have mercy!” I don’t mean that we should shout it out loud but we should do it with a trembling heart and conscience, with hope and despair…”
Translated by The Catalog of Good Deeds