THE NEED OF THE SACRIFICE OF THE ALTAR
From the Manual of the Catholic Church, 1906 ed.
Q. What need was there for the Sacrifice of the altar, since we were fully redeemed by the Sacrifice of the cross?
A. First, That we might have, in the Sacrifice of the altar, a standing memorial of the death of Christ.
Second, That the memory of our Savior’s passion being thus daily renewed, and presented to Almighty God, might be a continual means to draw down His blessing upon us and to thank Him for his daily favors in a manner worthy of Him, and to obtain pardon for the sins we are daily committing against Him.
Third, That the Christian people might have an efficacious means of approaching daily to God through our Savior Jesus Christ, who is the Victim here offered.
Fourth, That they might have, to the end of the world, an external Sacrifice, in which they might join together in offering supreme homage to God, 
as the servants of God had always done from the beginning of the world.
Fifth, That all the figures and sacrifices of the old law, and of Melchisedech, might be perfectly fulfilled, according to that of our Savior: “Amen I say unto you, till heaven and earth pass, one jot, or one title shall not pass from the law, till all be fulfilled,” Matt. v. 18.
Sixth, That by the Sacrifice of the altar, the fruits of His death might daily be applied to our souls.
Q. How are the fruits of our Savior’s death applied to our souls by the Mass?
A. Jesus Christ died upon the Cross for all mankind in general; that is, He offered to God a full and ample satisfaction for the injury done Him by the sins of the whole world. In the Mass, by mystically renewing, and presenting to His Father the death He suffered on the Cross, He obtains His [Heavenly Father’s] acceptance of the same for the actual benefit of those in particular for whom the Mass is offered; and, by this means, those graces which He merited for mankind in general by His death, are actually applied to, and bestowed upon our souls in such abundant manner, as our wants require and as our dispositions are capable of receiving.
