The Adornment of the Spiritual Marriage, by Jan van Ruysbroeck, , at sacred-texts.com
Out of kindliness springs compassion, which is a fellow-feeling with all men; for none can share the griefs of all, save him who is kind.
Compassion is an inward movement of the heart, stirred by pity for the bodily and ghostly griefs of all men. This compassion makes a man suffer with Christ in His passion; for he who is compassionate marks the wherefore of His pains and the way of His resignation; of His love, His wounds, His tenderness; of His grief and His nobleness; of the disgrace, the misery, and the shame He endured; of the way in which He was despised; of His crown; of the nails; of His mercifulness; of His destruction and dying in patience. These manifold and unheard-of sorrows of Christ, our Saviour and our Bridegroom, move all kindly men to pity and compassion with Christ.
Compassion makes a man look into himself, and recognize his faults, his feebleness in virtues and in the worship of God, his lukewarmness, his laziness, his many failings, the time he has wasted and his present imperfection in moral and other virtues; all this makes a man feel true pity and compassion for himself. Further, compassion marks the errors and disorders of our fellow-creatures, how little they care for their God and their eternal blessedness, their ingratitude for all the good things which God has done for them, and the pains He suffered for their sake; how they are strangers to virtue, unskilled and unpractised in it, but skilful and cunning in every wickedness; how attentive they are to the loss and gain of earthly goods, how careless and reckless they are of God, of eternal things, and their eternal bliss. When he marks this, a good man is moved to compassion for the salvation of all men.
Such a man will also regard with pity the bodily needs of his neighbours, and the manifold sufferings of human nature; seeing men hungry, thirsty, cold, naked, sick, poor, and abject; the manifold oppressions of the poor, the grief caused by loss of kinsmen, friends, goods, honour, peace; all the countless sorrows which befall the nature of man. These things move the just to compassion, so that they share the sorrows of all. But their greatest pain springs from this: that men are so impatient of this suffering, that they lose their reward, and may often earn hell for themselves. Such is the work of compassion and of pity.
This work of compassion and of common neighbourly love overcomes and casts out the third mortal sin, that is hatred or Envy. For compassion is a wound in the heart, whence flows a common love to all mankind and which cannot be healed so long as any suffering lives in man; for God has ordained grief and sorrow of heart before all the virtues. And this is why Christ says: Blessed are they that mourn: for they shall be comforted. And that shall come to pass when they reap in joy that which now, through compassion and pity, they sow in tears.