Only "through Christ, with Him and in Him" can we arrive to the Father.
The word “doxology” comes from the Greek “doxa” which means “glory”. Doxology, therefore, means glorification.
Each celebration of the Mass has this function of praise, of blessing, and of glorification. However, the Eucharistic Prayer is the heart of this liturgy. The Prayer begins with the preface, lifting our hearts up to the Father. Then comes the Sanctus, proclaiming God’s holiness and glory that fills the universe. At the end of the Eucharistic Prayer, the priest recites this concluding doxology, praising the Trinity. In this prayer, the priest elevates the Sacred Victim up high, above all temporal realities, and says:
“Through Him, with Him and in Him, in the unity of the Holy Spirit, all glory and honor is yours, almighty Father, for ever and ever.”
The Church believes in the mediation of Christ alone and His supreme Priesthood. Only “through Him, with Him and in Him” can we reach the Father. “No one comes to the Father except through me.” (Jn 14:6) We know that our deeds are pleasing to God through Christ. Our lives united to His life, to His death and to His resurrection, are glory and honor to the Trinity.
The Church exists to glorify God: this is precisely why the priestly Christian people have congregated together– to elevate toward God, in the Eucharist, the maximum praise possible and to gain, on behalf of all humanity, countless material and spiritual goods. This is why the Eucharist is where the Church completely manifests and expresses herself.
Now is a good time to point out the fact that the active participation of the faithful does not consist in reciting together with the priest this doxological prayer. According to the General Instruction of the Roman Missal, “The concluding doxology of the Eucharistic Prayer is spoken solely by the principal priest celebrant and, if this is desired, together with the other concelebrants, but not by the faithful.” (GIRM, 236)
The Christian people make the Eucharistic Prayer their own and complete the great Trinitarian Doxology by saying “Amen.” It is the most solemn Amen of the Mass. In the third century, the principal privileges of the Christian people were listed as: hearing the Eucharistic Prayer, pronouncing the Amen and receiving the Divine Bread. With this ‘Amen’, the faithful ratify the holy Sacrifice of the Mass. St. Augustine says, “To say ‘Amen’ means to endorse.” Even up through the Carolingian dynasty, the last words of the Canon were not spoken in silence so that the people could respond ‘Amen’ out loud.
The word ‘Amen’ is possibly the principal acclamation of the Christian liturgy. The term ‘Amen’ proceeds from the Old Covenant: "The Levites shall proclaim aloud to all the men of Israel... And all the people shall answer, 'Amen!'” (Dt 27:15-26; 1 Cron 16:36; Neh 8:6). According to different contexts, ‘Amen’ means: “This is it, this is the truth, so be it”.
The ancient ‘Amen’ continues to resound in the new covenant. It is the characteristic acclamation of the celestial liturgy. (Rev 3:14; 5:14, 7:11-12; 19:4) In Christian tradition, it conserves all of its ancient expressive vigor. (1 Cor 14:16; 2 Cor 1:20)
As in the whole liturgy, saying ‘Amen’ has a vital meaning. It shouldn’t be a mere response with the lips, but rather, it has the value of uniting us to the mystery that we celebrate. Saying ‘Amen’ means uniting ourselves with Christ, desiring to make our whole life a doxology, that is, a glorification of the Trinity, united to the Paschal mystery of the Redeemer.
An essential part of the Christian vocation is to be “the praise of His glory”. Once again we see how the liturgy should be lived. A summary of the glory of creation in Christ is found in the doxology. Through His obedience and love even unto the Cross, Christ has carried out the perfect glorification of the Father: “Father, glorify your Name” (Jn 17:5), and has achieved the perfect glorification of His humanity, united to the Incarnate Word: “Now glorify me, Father, with you, with the glory that I had with you before the world began.” (Jn 17:5) We must unite ourselves, with our lives, to this glorification of the Trinity. Uniting ourselves to Christ, offering our whole life with Him, joys and pains, success and failure, work and everything that we do, we will become praise of the glory of the Trinity “through Him, with Him and in Him.”