On the Sacrifice of the Mass--we need it and it continues throughout history as we are not perfect.
In Colossians 1:24, St. Paul states, 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. DR
There is a mystery of suffering in the Church. How many saints and even those who have died recently for the Faith, are martyrs? How many people suffer in charity and goodness for no apparent reason? If we are in sanctifying grace, that does not mean we shall have a smooth life. Quite the opposite.
St. Thomas Aquinas tells us that all the virtues were preached by Christ from the Cross.
His Passion was infinite in merit in their cause, but not in the effects. But, there is more.
Not because there is something lacking in Christ's suffering, which is infinite, God chose the effects would not take effect so that we can take part in the suffering, passion and death with those.
Prayers, sufferings and merits which we gain in suffering is planned and willed by God the Father, who wanted us to be part of our own salvation. We cooperate in the Passion of Christ and therefore merit higher places in heaven.
You may have never heard this before. Most of the priests in some seminaries teach that we only preach the Resurrection and not the Passion. I have heard this recently in a talk by Father Chad Ripperger. But, I heard this as a girl in both elementary and high school. The teaching of the Church has always maintained that we must gain merit.
God may want, says Father Ripperger, that God sometimes does not answer our prayers right away as He wants us to gain more merit. If our prayers are not answered immediately, even in the Mass, God is waiting for us to change, to grow, to gain more merit. Not everyone gets to heaven, Fr. reminds us. The efficacy of the Calvary sacrifice, he states, to those who are the "elect". People forget this. We do not believe in universal salvation, as Father reminds us.
Go, if you can, to daily Mass. It is part of His Will for us that we try and go to daily Mass. We are changed, which Fr. Ripperger reminds us, to sons and daughter of God, through baptism and the sacraments. Be a grace-pig. Go to Mass daily.