It is said that for handing on the faith the liturgy matters decisively, by the old adage lex orandi, lex credendi. A celebration may therefore not shrink into a formal performance. Its signs have to reach the mind and the heart, give living voice to the one faith of the Church, and make each believer more aware of belonging to the Body of Christ.

Only a participation that is fully conscious, and so schooled in the liturgy’s own language, is said to pass the faith on as a new life and not an abstract doctrine, a life that spreads “by attraction”. Augustine is called as witness: years afterwards he remembered weeping at the Church’s hymns, the voices running into his ears and the truth into his heart. By the loveliness of its signs and the force of the Word the liturgy is called the spring of the Church’s mission, letting the community give an account of its hope through lives changed by grace. Hence great care in the celebrations, and a mystagogy that walks the young through what they celebrate.

I desire therefore, first of all, that supplications, prayers, intercessions, and thanksgivings be made for all men: For kings, and for all that are in high station: that we may lead a quiet and a peaceable life in all piety and chastity. For this is good and acceptable in the sight of God our Saviour, Who will have all men to be saved, and to come to the knowledge of the truth.

e · 1 Timothy 2:1–4 · Douay-Rheims

^fObsecrationum quoque sacerdotalium sacramenta respiciamus, quae ab apostolis tradita in toto mundo, atque in omni catholica Ecclesia uniformiter celebrantur, ut legem credendi, lex statuat supplicandi.

Let us look also to the sacred rites of the priestly prayers, which, handed down from the apostles, are celebrated in the same way throughout the world and in every Catholic Church, so that the law of supplication may establish the law of belief.

f · Indiculus, ch. 8 (DH 246) · Latin; translation the commentator's

^gHow did I weep, in Thy Hymns and Canticles, touched to the quick by the voices of Thy sweet-attuned Church! The voices flowed into mine ears, and the Truth distilled into my heart, whence the affections of my devotion overflowed, and tears ran down, and happy was I therein.

g · Augustine, Confessions IX.6 · Pusey

^h… that the sheep of Christ may not suffer hunger, nor the little ones ask for bread, and there be none to break it unto them, the holy Synod charges pastors, and all who have the cure of souls, that they frequently, during the celebration of mass, expound either by themselves, or others, some portion of those things which are read at mass, and that, amongst the rest, they explain some mystery of this most holy sacrifice, especially on the Lord's days and festivals.

h · Trent, sess. XXII (1562), ch. 8 · Waterworth (1848)

ad e, f

The Indiculus argues from Paul's command: the Church prays everywhere for all, so all need grace. The prayer is the witness; the faith is what it witnesses. That is the axiom's first sense.

Pius XII kept its direction: the prayer expresses the faith, it does not legislate it. n. 92 cites the adage that way round.

☞ The checker

violation(lex_orandi_as_fixing( rite_w, q(eucharist_paschal)))

Read backwards, with the prayer fixing a doctrine, the axiom is refused.

ad g

n. 92's Augustine, whole. The voices into the ears, the truth into the heart, then the tears: signs that speak, then devotion. The gloss's order is his.

ad h

Trent's remedy for a Mass the people could not follow: pastors to expound the readings and the mystery during the celebration. That is n. 92's mystagogy, in 1562.

The chain

If the signs carry the faith, they must speak; if they speak, participation must be conscious; conscious participation needs formation. Each step follows from the one before.