Step aside, from all thoughts of the world, just come to God as a lover of God. Nothing so gratifies the Lord as supplication offered in the midst of tears," he says. Sorrow generates heat, heat means literally heat also, but also psychic concentration heat - it dissolves our inner hardness. Your callousness, our material nature is for a time being softened. At that time, if you hold on intensely to God, it has a benefit.
"Do not pray for the fulfillment of your wishes, for they may not accord with the will of God. But pray as you have been taught, saying: Thy will be done in me (cf. Luke 22:42). Always entreat Him in this way - that His will be done. For He desires what is good and profitable for you, whereas you do not always ask for this." - Evagrius Ponticus.
Swami Sarvapriyananda speaks on Evagrius's teachings on prayer.