“Amen” means “So be it.” It means “I believe.” It means “The truth has been spoken.” And it’s a little like clicking the “Send” button after you’ve written an email. It gives your prayer the wings it uses to fly toward God in heaven.
We conclude many prayers at Mass with an Amen. The Glory to God, the Collect, the Creed, the Prayer over the Offerings, the Doxology after the Lord’s Prayer, and the Prayer after Communion all end with the word “Amen.” When you receive the Body and Blood of the Lord at Communion, you answer “Amen.”
But amid all these Amens, one is traditionally called “great,” the one that concludes the Eucharistic Prayer.
The Great Amen is great because of what it says Amen to. Throughout the Eucharistic Prayer, we have been praying in thanksgiving for the wonder-
ful things God does for us, and we have been praying in petition for the living and the dead. Most importantly, we have been praying that the Holy Spirit would change the bread and wine on the altar into the Body and Blood of Christ. This prayer, the most powerful prayer in human history, concludes with an Amen that can only be called “great.”
Because of the significance of this Amen, it is one of the acclamations that we are encouraged to sing at Mass (General Instruction of the Roman Missal, 40). Usually, the priest will sing the preceding words, which refer to Christ: “Through him, and with him, and in him, O God almighty Father, in the unity of the Holy Spirit, all glory and honor is yours, almighty Father, for ever and ever.”
To those words, all we can say and all we must say is “Amen.”