From: Luke 6:36-38
Love of Enemies (Continuation)
(Jesus said to his disciples,)  "Be merciful, even as your Father is merciful.  "Judge not, and you will not be judged; condemn not, and you will not be condemned; forgive, and you will be forgiven;  give, and it will be given to you; good measure, pressed down, shaken together, running over, will be put into your lap. For the measure you give will be the measure you get back."
36. The model of mercy which Christ sets before us is God Himself, of whom St. Paul says, 'Blessed be the God and Father of our Lord Jesus Christ, the Father of mercies and God of all comfort, who comforts us in all our afflictions" (2 Cor 1:3-4). "The first quality of this virtue", Fray Luis de Granada explains, "is that it makes men like God and like the most glorious thing in Him, His mercy (Lk 6:36). For certainly the greatest perfection a creature can have is to be like his Creator, and the more like Him he is, the more perfect he is. Certainly one of the things which is most appropriate to God is mercy, which is what the Church means when it says that prayer: 'Lord God, to whom it is proper to be merciful and forgiving...'. It says that this is proper to God, because just as a creature, as creature, is characteristically poor and needy (and therefore characteristically receives and does not give), so, on the contrary, since God is infinitely rich and powerful, to Him alone does it belong to give and not to receive, and therefore it is appropriate for Him to be merciful and forgiving" ("Book of Prayer and Meditation", third part, third treatise).
This is the rule a Christian should apply: be compassionate towards other people's afflictions as if they were one's own, and try to remedy them. The Church spells out this rule by giving us a series of corporal works of mercy (visiting and caring for the sick, giving food to the hungry, drink to the thirsty...) and spiritual works of mercy (teaching the ignorant, correcting the person who has erred, forgiving injuries...): cf. "St Pius X Catechism", 944f.
We should also show understanding towards people who are in error: "Love and courtesy of this kind should not, of course, make us indifferent to truth and goodness. Love, in fact, impels the followers of Christ to proclaim to all men the truth which saves. But we must distinguish between the error (which must always be rejected) and the person in error, who never loses his dignity as a person even though he flounders amid false or inadequate religious ideas. God alone is the judge and searcher of hearts; He forbids us to pass judgment on the inner guilt of others" (Vatican II, "Gaudium Et Spes", 28).
38. We read in Sacred Scripture of the generosity of the widow of Zarephath, whom God asked to give food to Elijah the prophet even though she had very little left; He then rewarded her generosity by constantly renewing her supply of meal and oil (1 kings 17:9ff). The same sort of thing happened when the boy supplied the five loaves and two fish which our Lord multiplied to feed a huge crowd of people (cf. Jn 6:9)-a vivid example of what God does when we give Him whatever we have, even if it does not amount to much.
God does not let Himself be outdone in generosity: "Go, generously and like a child ask Him, 'What can You mean to give me when You ask me for "this"?'" ([St] J. Escriva, "The Way", 153). However much we give God in this life, He will give us more in life eternal.
Source: "The Navarre Bible: Text and Commentaries". Biblical text taken from the Revised Standard Version and New Vulgate. Commentaries made by members of the Faculty of Theology of the University of Navarre, Spain. Published by Four Courts Press, Kill Lane, Blackrock, Co. Dublin, Ireland. Reprinted with permission from Four Courts Press and Scepter Publishers, the U.S. publisher.