From Dom Guéranger's The Liturgical Year.

FIVE days after the martyrdom of the Virgin Emerentiana, the parents of the glorious Saint Agnes visited the tomb of their child, during the night, there to weep and pray. It was the eighth day since her martyrdom. Whilst they were thinking upon the cruel death, which, though it had enriched their child with a Martyr's palm, had deprived them of her society, Agnes suddenly appeared to them: she was encircled with a bright light, and wore a crown on her head, and was surrounded by a choir of virgins of dazzling beauty. On her right hand there stood a beautiful white lamb, the emblem of the Divine Spouse of Agnes.

Turning towards her parents, she said to them: 'Weep not over my death: for I am now in heaven, together with these virgins, living with him whom I loved on earth with my whole soul.'

It is to commemorate this glorious apparition that the holy Church has instituted this Feast, which is called Saint Agnes' Second Feast (Sanctœ Agnetis secundo). Let us pray to this fervent spouse of the Divine Lamb, that she intercede for us with him, and present us to him in this life, until it be given to us to possess him face to face in heaven. Let us unite with the Church in the following Prayer, which she uses in today's Office:

Ant. Stans a dextris ejus Agnus nive candidior, Christus sibi Sponsam et Martyrem consecravit.

℣. Specie tua, et pulchritudine tua.
℟. Intende, prospere procede et regna.

Oremus

Deus qui nos annua beatæ Agnetis Virginis et Martyris tuæ solemnitate lætificas: da quæsumus, ut quam veneramur officio, etiam piæ conversationis sequamur exemplo. Per Christum Dominum nostrum.

Amen.
Ant. Standing at her right hand as a Lamb whiter than snow, Christ consecrated her to himself as his Spouse and Martyr.

℣. With thy comeliness and thy beauty.
℟. Set out, proceed prosperously, and reign.

Let us Pray

O God, who rejoicest us by the yearly solemnity of blessed Agnes, the Virgin and Martyr: grant, we beseech thee, that we may imitate her life to whose memory we pay this honour. Through Christ our Lord.

Amen.