The Easter Vigil represents the central moment of the sacred Triduum and of the entire liturgical year: it is the "mother of all vigils" (Saint Augustine), because on this night the Church awaits and watches over the resurrection of Christ and celebrates it in the Sacraments.
Despite its resemblance to the Roman Rite, the Church of Milan - and in particular the liturgy of the Duomo - has maintained a series of peculiarities. In fact, the Ambrosian liturgy has reread way the Lucerne part of the Vigil in an unusual way, provides for its own biblical catechesis and has preserved, similarly to what happens on Holy Thursday at the Mass "in the Lord's Supper", also the ancient Eucharistic Canon of this night.
The rite that marks the beginning of the Easter Vigil is the Service of Light, brought by the catechumens who will receive the Sacraments this night: in fact, from the day before and from the proclamation of the death of the Lord, as a sign of mourning, all candles have been extinguished. Using the blessed candle - once coming from the nearby church of San Sepolcro, a Milanese memory of the holy places of the Passion of the Lord - the Archbishop lights the great Easter candle, which guides the procession to the high altar, while the cathedral is gradually illuminated.
From the pulpit, the Preconio (the "Exúltet", from the incipit of the Latin text sung by the deacon) is sung, an ancient liturgical hymn, which in the typical version of the Ambrosian tradition (also characterized by its own melody) dates back to the fifth century. The Preconio, in which the different images of the lamb, the shepherd, the water and the bread find their perfect realization in Jesus risen from the dead, represents in a certain way the "synthesis" of the entire celebration. The Ambrosian text, interpreting in a unique way the image of the light that comes from the Candle (compared to the "column of fire" of the Exodus and the "star" guide of the Magi), describes Easter night as the night in which "preannouncements and prophetic facts of various millennia come true" and presents the Sacraments as a sign of participation in the Easter of the Lord. During the singing of the Preconio, according to the Cathedral's own liturgy, at different times linked to the text of the Inno, the candles of the Duomo and the candles of the altar are relit, using the flame of the Easter candle, placed next to the ambo.
This is followed by the long biblical catechesis, composed of nine Readings, taken from the two Testaments, in which all the fundamental events of the history of salvation are recounted, starting from creation to the resurrection and exaltation of Christ. At the end of the six Readings of the First Testament, the solemn Announcement of the Resurrection resounds. The Archbishop, wearing the mitre on his head and carrying the crosier, sings "Christus-Dóminusresurréxit! "(Christ the Lord is risen) to the three sides of the altar, and immediately the bells - which have remained "silenced" since the announcement of the death of the Lord, are rung - and the organ is played, as a sign of celebration. Not the singing of the Glory, therefore, as happens in the corresponding celebration of the Roman Rite, but the triple Announcement of the Resurrection marks the culmination of the Ambrosian Easter Vigil. A particularity, which presents a strong parallelism with Byzantine liturgy, borrowed from an ancient tradition already in use in Jerusalem, during the fifth and sixth centuries.
The third part of the Vigil is marked by the administration of the Sacraments of Christian Initiation (Baptism, Confirmation, Eucharist). Every year, in the Cathedral, several adult Catechumens receive the Sacraments from the Archbishop on this very night and are dressed in the white robe, a sign of the new life of grace, which springs from the baptismal regeneration. As if to make visible the image - recalled by the Preconio - of the "column of fire that shines and guides the redeemed to the waters that give salvation", the procession of the Catechumens to the Borromean baptismal font, placed at the entrance of the Cathedral, is guided by the Easter candle.