This is the third in the ongoing series of sermons on the Beatitudes.  This one was delivered on Quinquagesima Sunday by Canon William Avis of the Institute of Christ the King Sovereign Priest: 
“Blessed are those who mourn, for they shall be comforted.” 
Introduction—Vanities of the World This Beatitude is acontradiction to the World 
Frivolity, licentiousness, Mardi Gras! “Vanity of vanities,said Ecclesiastes: vanity of vanities, and all is vanity.” [Eccles. 1:2] “Isaid in my heart: I will go, and abound with delights, and enjoy good things.And I saw that this also was vanity. Laughter I counted error: and to mirth I said: Why are you vainlydeceived?” [Eccles. 2:1-2]  What shall wesay, dear faithful, about this contradiction between the worldly and the just,between the disciples of mammon and the followers of Christ?  The world clamors after pleasure,exhilaration and the latest thrill.  Themoment someone is unhappy, it gives him a pill. “How can sadness be good?”sneers the world as it adds, “Blessed are certainly not those who mourn! Andall who shall rejoice must come to me.” But Christ, the True Light dispellingthe darkness of this world, declares to us, “Blessed are they who mourn, forthey shall be comforted,” [Matthew 5:5] and “Woe to you that now laugh: for youshall mourn and weep.” [Luke 6:25] 
1. Of what sadness is this mourning 
“What kind of mourning is here recommended in thisbeatitude,” asks the reverend Bishop Challoner, “Not worldly sadness of whichit is written, Eccles. xxx. 25, ‘Sadness hath killed many, and there is noprofit in it;’ and 2 Cor vii. 10, ‘The sorrow of this world worketh death.’ Nota sullen melancholy, or any such mourning as is turbulent, or accompanied withthe impatient wishes for death, or anxious solicitudes or despondency; but amore calm and peaceful mourning, viz., of compunction for our sins, dailybewailing them in the sight of God, and doing penance for them.”[Meditations]  It often happens thatthose who leave the world and its sordid pleasures experience some sadness attheir apparent loss.  Saint Augustineexplains this thus, “Mourning is sorrow arising from the loss of things helddear; but those who are converted to God lose those things which they wereaccustomed to embrace as dear in this world: for they do not rejoice in thosethings in which they formerly rejoiced; and until the love of eternal things bein them, they are wounded by some measure of grief.”
“[Christ] designated not simply all that mourn, but all thatdo so for sins,” expounds Saint John Chrysostom, “Since surely that other kindof mourning is forbidden, and that earnestly, which relates to anything of thislife. This Paul also clearly declared, when he said, ‘The sorrow of the worldworks death, but godly sorrow works repentance unto salvation,’…These then HeHimself too calls blessed, whose sorrow is of that kind; yet not simply themthat sorrow did He designate, but them that sorrow intensely. Therefore He didnot say, they that sorrow, but they that mourn…[And] He bids us mourn, notonly for our own, but also for other men’s misdoings. And of this temper were thesouls of the saints: such was that of Moses, of Paul, of David.”  [Homilies on the Gospel of Saint Matthew] 
2. Penance-How we live this Beatitude 
Helas! What sadness should strike our hearts when weconsider the immensity of our own iniquity? How many tears should pour forth from our eyes at seeing our God, theSupreme Goodness, offended by so many sins? How are we to mourn, so that we maybe consoled by God’s gracious mercy?  “Nowit belongs to right reason than one should grieve for a proper object of griefas one ought to grieve, and for an end for which one ought to grieve [III q. 85a 1],” Saint Thomas Aquinas teaches. “Penance is a special virtue not merelybecause it sorrows for evil done…, but also because the penitent grieves forthe sin he has committed, inasmuch as it is an offense against God, andpurposes to amend. Now amendment for an offense committed against anyone is notmade by merely ceasing to offend, but it is necessary to make some kind ofcompensation [III q. 85 a 3].” 
We who desire to becomforted by God’s mercy must mourn through acts of penance, to offer Him goodworks in compensation for the evil that we have committed.  In a few days hence, we will hear from God“Be converted to Me with all your heart, in fasting, and in weeping, and inmourning [Joel 2:12],” and the great fast of Lent will begin.  It is a time for us to turn back to the Lordlamenting by penitential acts in expiation for sin.  Already today we have an opportunity with the40 hours devotion which will begin after (the 10 a.m.) Mass to offer reparationto Christ in the most Blessed Sacrament. 
3. Spiritual joy and consolation 
Now if we do mourn and lament over our sins, we shall becomforted. Saint John Chrysostom states: “Wherefore, if you will be comforted,mourn… For when God does comfort, though sorrows come upon you by the thousandslike snow-flakes, you will be above them all. Since in truth, as the returnswhich God gives are always far greater than our labors; so He has wrought inthis case, declaring them that mourn to be blessed, not after the value of whatthey do, but after His own love towards man. For they that mourn, mourn formisdoings, and to such it is enough to enjoy forgiveness, and obtain wherewithto answer for themselves. But forasmuch as He is full of love towards man, Hedoes not limit His recompense either to the removal of our punishments, or tothe deliverance from our sins, but He makes them even blessed, and imparts tothem abundant consolation.” [Sermons on Saint Matthew]  Truly blessed will we be to receive fromChrist comforts which will have no end, and woe to those who seek from theworld their ease which one day will perish and be no more. 
Conclusion—towards the world or towards heaven 
My dear faithful, the choice is laid before us either tomourn now in works of penance so that we might rejoice forever, “they that sowin tears shall reap in joy [Ps. 125:5], or to gloat in the hedonisms of thisworld making that we lament in eternity. Which will you choose?  Considerthis world’s fleeting pleasures that soon will but ash and naught, and wouldyou forfeit the eternal gifts of God for such things as these? Amen.