Prayer Of St Ambrose Before Mass

Before you open the missal, there is a short prayer most people skip

The Prayer Of St Ambrose Before Mass comes right after the Entrance Antiphon in the Extraordinary Form of the Roman Rite. It sits between the Introit and the Confiteor, and it is technically part of the prayers at the foot of the altar. Many priests and servers treat it as a transitional formality. They mumble it fast and move on to the confessions. That is a mistake, but it is also the default setting for most parish liturgies. The Latin reads: "Introibo ad altare Dei, ad Deum qui laetificat juventutem meam. Adjutorium nostrum in nomine Domini, qui fecit caelum et terram. Gloria Patri et Filio et Spiritui Sancto. Sicut erat in principio et nunc et semper et in saecula saeculorum. Amen."

Translation: I will go in unto the altar of God, unto God who giveth joy to my youth. Our help is in the name of the Lord, who made heaven and earth. Glory be to the Father, and to the Son, and to the Holy Ghost. As it was in the beginning, is now, and ever shall be, world without end. Amen.

The Prayer Of St Ambrose Before Mass in practice

The reason this prayer exists is not literary. It is functional. Psalm 42 expresses the movement from the nave toward the altar, which in cathedral architecture was literally a physical threshold you crossed before entering the sanctuary. St. Ambrose attributed these words to his own preparation before celebrating Mass, hence the traditional name. The rubrics assign it to the priest, though the server or choir may respond. In the usus antiquior, the priest says the first half, then the responses come back, then he finishes with the Gloria Patri. Here is what most guides leave out. The prayer is not a standalone devotion. It is a doorway. After this comes the Confiteor, then the Asperges or the introductory versicles, then the Kyrie. If you say the Ambrose prayer too slowly, you compress the penitential section that follows. If you rush it, you have already started the Mass before the priest has actually entered the sacred space mentally. The timing matters more than people admit. I once dealt with a situation where a priest who was new to the Tridentine Mass said the entire prayer at a normal speaking pace without pausing for the responses. The server had no time to insert the proper response after "Adjutorium nostrum" and ended up saying it on top of the priest's continuation. It sounded like two people reading different parts of the script at the same time. The fix was simple: I asked the server to wait a beat after the priest says "Dei" before answering "qui laetificat juventutem meam," and then pause again after "meam" for the priest to say "Adjutorium nostrum." The break is small but it prevents the overlap entirely. We marked it lightly in the ritual booklet with a tiny forward slash. That solved the problem for the rest of the year.

There is a second nuance that trips up people who are learning this rubric. The phrase "Introibo ad altare Dei" is Psalm 42:3. Some older missals print it with a punctuation that suggests a slight caesura after "Dei." Most modern reprints smooth it into a single breath. The difference is subtle, but if you chant it, the caesura changes where you put the accent. For spoken recitation it does not matter much. For chanting, it shifts the melodic formula. The Gloria Patri that closes the prayer is important. It is not an afterthought. It transforms the psalm from a petition into a Trinitarian acknowledgment before the confessions begin. Rubrically, the priest is supposed to make the sign of the cross on himself at "Gloria Patri." If you miss it, the prayer still counts. But the gesture is part of the liturgical grammar, and its absence makes the transition into the Confiteor feel abruptly clinical.

Where to find the text and why some editions mislabel it

The prayer appears in the 1962 Missale Romanum on page 9, in the section titled "Preparation for Mass" under the prayers at the foot of the altar. It also appears in the 1970 Missal, though with modified rubrics that many still follow. You will find it in most Latin-English bilingual missals and in online repositories like Reményi or Missa.net. The text is stable. There is very little textual variation across editions. The catch is the heading. Some sources call it the "Prayer of St. Ambrose." Some call it the "Introibo." Some label it simply as part of the foot-of-the-altar prayers without naming it. The attribution to Ambrose is traditional but not strictly documented in his surviving writings. The prayer appears in sacramentaries that predate Ambrose's direct influence, which is why some scholars prefer the neutral label. For liturgical use, the name does not change the rubrics. It only affects how people search for it. If you are looking for the full text with rubrical notes, the best free resource is the English-Latin Missal published by Ignatius Press or the online PDF from Trask's Archive. Both are accurate. The Ignatius edition includes a brief introduction that explains the penitential context. The Trask PDF is a raw scan of the 1962 typical edition with no commentary, which some people prefer because it avoids editorial interference.

Common mistakes and how to avoid them

Most people who learn this prayer for the first time do three things wrong. First, they confuse it with the Judgment I pray for (the "Judicium" prayer that follows). The two are separate. The Ambrose prayer is verse and response. The Judgment prayer is a longer private devotion. Second, they say the Gloria Patri without the accompanying bow or sign of the cross. Third, they rush through it because they think it is optional. It is not optional in the Extraordinary Form. The rubrics require it before the Confiteor. A less obvious mistake is omitting the response "Sicut erat in principio" when chanting. In plain recitation the server or choir says the full doxology back. In the short responsorial form, the server says only "Sicut erat in principio et nunc et semper et in saecula saeculorum. Amen." The difference matters if you are leading a sung Mass. Using the long form when the short form is indicated breaks the chant structure. There is also a practical issue with language. The prayer is in Latin by universal rubrical requirement in the Extraordinary Form. Some parishes that use the Ordinary Form substitute a vernacular version, but that is a pastoral adaptation, not the norm. If you are preparing to say this in a traditional setting, assume Latin unless told otherwise.

When this prayer does not work the way you expect

The biggest limitation is contextual. The Prayer Of St Ambrose Before Mass is tied to the traditional altar arrangement. In churches where the altar is positioned so the priest faces the people directly, the gesture of "going in unto the altar" loses its physical meaning. The prayer is still valid. The rubrics do not change. But the original symbolism of moving from the congregation area toward the sanctuary becomes abstract. Some priests handle this by making a more pronounced movement toward the altar before saying it. Others simply say it standing at the book. Neither is wrong, but the former preserves the intention better. Another edge case: if the priest arrives late and the congregation has already begun the Kyrie, there is no time for the foot-of-the-altar prayers. The priest goes straight to the altar and begins at the Confiteor or even skips ahead. This happens more often than most liturgists want to admit. It is not ideal, but the Mass remains valid. The prayer is devotional in nature, not essential to the sacrament. For anyone learning this, the practical advice is straightforward. Say it slowly enough to hear your own voice. Pause for the responses. Make the sign of the cross at the Gloria Patri. Do not merge it with the Confiteor. If you are chanting, learn the responsorial form separately from the full form. And if you are the server, do not anticipate the response. Wait for the pause. One extra second of silence is better than a collision.