SOME OF THE GRACES AND FRUITS TO BE DERIVED FROM DEVOUT ATTENDANCE AT HOLY MASS:
1. For your salvation, God the Father sends His beloved Son down from Heaven.
2. For your salvation, the Holy Spirit changes bread and wine into the true Body and Blood of Christ.
3. For your sake, the Son of God comes down from Heaven and conceals Himself under the form of the sacred Host.
4. He even abases Himself to such an extent as to be present in the minutest particle of the sacred Host.
5. For your salvation, He renews the saving mystery of the Incarnation.
6. For your salvation, He is born anew into the world in a mystic manner whenever Holy Mass is celebrated.
7. For your salvation, He performs upon the altar the same acts of worship that He performed when on earth.
8. For your salvation, He renews His bitter Passion in order that you may participate in it.
9. For your salvation, He mystically renews His death and sacrifices for you His precious life.
10. For your salvation, He sheds His Blood in a mystic manner and offers it up for you to the Divine Majesty.
11. With this Precious Blood He sprinkles your soul and purifies it from every stain.
12. For you, Christ offers Himself as a true burnt offering and renders to the Godhead the supreme honor which is its due.
13. By offering this act of worship to God, you make reparation for the glory which you have failed to give Him.
14. For you Christ offers Himself to God as a sacrifice of praise, thus atoning for your omissions in praising His Holy Name.
15. By offering to God this oblation which Christ offers, you give Him greater praise than do the holy Angels.
16. For you Christ offers Himself as a perfect sacrifice of thanksgiving, making compensation for all failures on your part to render thanks.
17. By offering to God Christ's act of thanksgiving, you make ample acknowledgment of all the benefits He has bestowed upon you.
18. For you Christ offers Himself as the All Powerful Victim, reconciling you to the God who you have offended.
19. He pardons you all your venial sins, provided you are firmly resolved to forsake them.
20. He also makes reparation for many of your sins of omission; when you left undone the good you might have done.
21. He removes many of the imperfections attaching to your good deeds.
22. He forgives you the sins, unknown or forgotten, which you have never mentioned in Confession.
23. He offers Himself as a victim to make satisfaction for a part, at least, of your debts and transgressions.
24. Each time you hear Mass, you can do more to pay the penalty due to your sins than by the severest work of penance.
25. Christ places to your credit a portion of His merits, which you may offer to God the Father in expiation of your offenses.
26. For you Christ offers Himself as the most efficacious peace-offering, interceding for you as earnestly as He interceded for His enemies on the Cross.
27. His Precious Blood pleads for you in words as countless as the drops which issued from His sacred veins.
28. Each of the adorable wounds His Sacred Body bore is a voice calling aloud for mercy for you.
29. For the sake of this propitiatory Victim, the petitions proffered during Mass will be granted far sooner than those that are proffered at other times.
30. Never can you pray so well as while present at Mass.
Fr. Martin von Cochem (The Incredible Catholic Mass)
note: Of course all mortal sins need to be forgiven in the holy Sacrament of Confession…