Paul smiled at the boy whom he had known only a few short weeks, but whom he had already loved as a son. "Was Our Lord afraid of danger?" he said mildly. "Did He run away from suffering?" "N-no."
"Who now rejoice in my sufferings for you, and fill up those things that are wanting of the sufferings of Christ, in my flesh, for his body, which is the church." St. Paul (Colossians 1:24)
Catholic author Mary Fabyan Windeatt in her 1949 book "Saint Paul the Apostle" showed how when we sin we injure Jesus, again, in His Church which is his Mystical Body:
[Paul said,] "When one part of the human body is injured, the whole body suffers. It is the same way with the Mystical Body of Christ."
[...]
"I mean that when any one of us sins, the whole Church is hurt. Not just ourselves."
This was something which deeply disturbed those newcomers who had never read Paul's letter to the Church in Rome. A sin, even a very small sin, could wound the Mystical Body of Christ, even as His human body had been wounded during the Passion? Oh, no!
"Yes," said Paul emphatically. "it's true." Then, noting the shadow which had fallen upon several faces: "but it's also true that one good deed performed in the state of grace, even a very small deed, has just the opposite effect." At this there was a murmur of astonishment. "You don't mean that the whole Church profits from a single good deed, master?"
Paul nodded eagerly. "Yes, That's just what I mean. Now do you see why we should love our neighbor and do all that we can to help him?" (Pages 194-195)
Not only our good deeds when done in the state of grace profit Jesus in His Mystical Body which is the Church, but most of all the Mass infinitely profits us and the world in atoning for sin and giving grace to be the adopted children of God the Father.
Windeatt wrote:
Paul explained to these Christian brethren how the all-holy Sacrifice of the New Law, the Eucharistic Sacrifice (which would later become known as the Mass), infinitely surpassed the animal sacrifices of the Old Law. (Page 212)
Also, our prayers outside of Mass and sufferings when united to Christ bring grace to all.
There is an old four page pamphlet titled "The Apostolate of Suffering" which on the cover has a drawing of Jesus on the Cross saying to us:
"Give me your hopelessness, unhappiness, failure, bitterness, misery, regrets, desolation, instability, frustration, sorrow, heartaches, struggle, pain, fears, poverty, worry, loneliness, regrets, frustration, rejection, indecision, helplessness, fatigue, anxiety, [etc...]."
The pamphlet, moreover, says Don't Waste Suffering! Pay the Ransom - for Souls:
Why should there be an Apostolate of Suffering?
I have been redeemed by the Cross. Therefore I must cooperate in the salvation of souls. I can be and I desire to be an apostle in my sufferings. Tears shed without love are wasted and embitter the soul. To weep with love consoles, sanctifies and redeems. No one is nearer the Crucified King.
Fr. Mateo, SS.CC. in the pamphlet, writes:
Let those who are ill, those who suffer, those whose hearts are breaking under the Cross, listen to the words of life, of comfort and of hope that I address to them in the name and for the glory of the heart of Jesus.
The world is going astray along a path of unbridled sensuality. You who are suffering and ill can stop thousands of souls on this downward path; you can rescue sinners and be apostles in your pain and weariness. You can purify, make reparation, and save souls by offering your sufferings as an apostolate of love.
Vanity, frivolity, forgetfulness of God, and outrages against His Law daily threaten to fill hell with souls. For love of Jesus, I beg you who are in anguish of soul to offer your family troubles, your sorrows and mental anguish as a missionary apostolate. Give them all to Him.
Priests and religious need help in their sublime mission; you, whose hearts are torn with sorrow and trouble of every kind, you who are misunderstood, families in mourning, orphans, do not lose your golden treasure, do not waste your precious tears – perhaps a father, a husband, a brother or a son is in danger of eternal death. Offer your sufferings, in the Chalice of Mary’s heart to Jesus Who thirsts for souls.
All you who suffer, do not forget that sorrow sanctified by love, becomes the holiest of missions, the most persuasive of sermons, the most fruitful of apostolates. So preach the Social Reign of the Heart of Jesus, even while you are nailed to the cross.
Mary Fabyan Windeatt in her 1949 book shows the above is the secret of true happiness and meaning in this life:
Paul smiled at the boy whom he had known only a few
short weeks, but whom he had already loved as a son. "Was Our Lord
afraid of danger?" he said mildly. "Did He run away from suffering?"
Paul had found the secret of happiness in this world. He desired nothing but the knowledge of Christ, for himself and others. As a result, death held no terror for him. After all, how could it. In a sense he already died, for his will was completely united to the Will of God."
[...]
"Rejoice in the Lord always. Again, I say, rejoice." Finally: "May the peace of Christ, which surpasses all understanding, guard your hearts and minds in Jesus Christ."
Pray an Our Father now for reparation for the sins committed because of Francis's Amoris Laetitia.