First of all, Elder Paisios tells us that, for love to blossom in the heart, we must pray with pain of heart. Once he was asked, "We pray, Elder, and our thoughts go here and there. Why?"
"Because it is prayer without pain!" replied the Elder. "To pray with the heart, we must hurt. Just as when we hit our hand or some other part of our body, our mind (nous) ("Nous: the highest faculty or power of the human soul, called by the Holy Fathers "the eye of the soul," St. John Damascene, and "the spiritual nature of man," St. Isaac the Syrian) is gathered to the point we are hurting, so also for the mind to gather in the heart, the heart must hurt."
The Elder was then asked, "How can we preserve ourselves in this state when we don’t have some problem, some pain?"
He replied, "We should make the other’s pain our own!! We must love the other, must hurt for him, so that we can pray for him. We must come out little by little from our own self and begin to love, to hurt for other people as well, for our family first then for the large family of Adam, of God".
At another time the Elder said, "The more one hurts, the more divine consolation one receives, because otherwise it is not possible to stand the pain... God especially consoles those who hurt for others".
To his spiritual children the Elder wrote: "To some people your love will be expressed with joy and to others it will be expressed with your pain. You will consider everyone your brother or your sister, for we are all children of Eve (of the large family of Adam, of God). Then, in your prayer you will say: ‘My God, help those first who are in greater need, whether they are alive or reposed brothers in the Lord.’ At that point, you will share your heart with the whole world and you will have nothing but immense love, which is Christ"