Today's Gospel reading speaks primarily to the third aspect (almsgiving). It is the "parable" of Lazarus and the rich man. And it is fittingly heard during Lent so that we might remember that sacrifice without mercy is no true sacrifice. The beginning of St Cyril of Alexandria's commentary on this parable is particularly poignant.
It is necessary, I think, in the first place to mention, what was the occasion that led to [Our Lord] speaking of these things; or what Christ intended to illustrate in so excellently sketching and describing the parable set before us. The Savior, therefore, was perfecting us in the art of well-doing, and commanding us to walk uprightly in every good work, and to be in earnest in adorning ourselves with the glories which arise from virtuous conduct. For He would have us to be lovers one of another, and ready to communicate; prompt to give, and merciful, and careful of showing love to the poor, and manfully persisting in the diligent discharge of this duty. And He especially admonished the rich in this world to be careful in so doing; and to guide them into the way which altogether becometh the saints, He said: "Sell your possessions, and give alms; make you purses that grow not old; a treasure that faileth not for ever in heaven." [Lk 12.33]
Now the commandment indeed is beautiful, and good, and salutary; but it did not escape His knowledge, that it is impossible for the majority to practice it. For the mind of man has ever been, so to speak, infirm in the discharge of those duties which are arduous and difficult; and to abandon wealth and possessions and the enjoyment which they give, is not a thing very acceptable to any, inasmuch as the mind is early clothed and entangled, as it were, in indissoluble cords, which bind it to the desire of pleasure.
Being good and loving unto men, therefore, He has provided for them a special kind of help, lest eternal and never ending poverty should follow upon wealth here, and everlasting torment succeed to the pleasures of the present time. "For make for yourselves friends," He says, "of the unrighteous mammon: that when it has failed, they may receive you into eternal tabernacles." This then is the advice of One providing them with something which they can do. For it, He says, ye cannot be persuaded to give up this pleasure-loving wealth, and to sell your possessions, and make distribution to those who are in need, at least be diligent in the practice of inferior virtues.
"Make for yourselves friends of the unrighteous mammon;" that is, do not consider your riches as belonging to yourselves alone; open wide your hand to those who are in need; assist those in poverty and pain; comfort those who have fallen into extreme distress; console with those who are in sorrow, or oppressed with bodily maladies, and the want of necessaries; and comfort also the saints who embrae a voluntary poverty that they may serve God without distraction. Nor shall your so doing be unrewarded. For when your earthly wealth abandons you, as ye reach the end of your life, then shall they make you partakers of their hope, and of the consolation given them by God. For being good and kind to man, He will lovingly and bontifully refresh those who have labored in this world; and more especially such as have wisely and humbly and soberly borne the heavy burden of poverty.
Similar advice the wise Paul also gives to those who live in wealth and abundance respecting those in misery: "Your abundance shall be to supply their falling short: in order htat also their abundance may supply your falling short." [2 Cor 8.14] But this is the advice of one who enjoins that simply which Christ spake, "Make to yourselves friends of the unrighteous mammon;" so that the commandment is well worthy of our admiration. (St Cyril of Alexandria, "Homily 111," Commentary on the Gospel of Saint Luke, 451-452)