Tremendous Value of the Mass

At the hour of death the Holy Masses you have heard devoutly will be your greatest consolation. God forgives you all the venial sins which you are determined to avoid. He forgives you all your unknown sins which you never confessed. The power of Satan over you is diminished.
Every Mass will go with you to Judgment and will plead pardon for you. By every Mass you can diminish the temporal punishment due to your sins, more or less, according to your fervor. By devoutly assisting at Holy Mass you render the greatest homage possible to the Sacred Humanity of Our Lord.
Through the Holy Sacrifice, Our Lord Jesus Christ supplies for many of your negligences and omissions.
By piously hearing Holy Mass you afford the Souls in Purgatory the greatest possible relief. One Holy Mass heard during your life will be of more benefit to you than many heard for you after your death. Through Holy Mass you are preserved from many dangers and misfortunes which would otherwise have befallen you. You shorten your Purgatory by every Mass. During the Holy Mass you kneel amid a multitude of holy Angels, who are present at the Adorable Sacrifice with reverential awe. Through Holy Mass you are blessed in your temporal goods and affairs.
When you hear Holy Mass devoutly, offering it to Almighty God in honor of any particular Saint or Angel, thanking God for the favors bestowed on him, etc. you afford that Saint or Angel a new degree of honor, joy and happiness, and draw his special love and protection on yourself.
Every time you assist at Holy Mass, besides other intentions, you should offer it in honor of the Saint of the Day.

-taken from a pamphlet