The textual edition of this sixth motet in the cycle Ave domine Iesu Christe is based on Librone 1 (ff. 167v–168r), where it was copied by Scribe A.
The copyist introduced some mistakes: for instance, he wrote ‘munsti’ in T instead of mundum, ‘nos’ instead of nobis, and ‘auxiliaris’ instead of the grammatically needed auxilieris in all voices.
Following the loco rubric, this motet was sung at the Elevation of the Host (‘ad Elevationem’) and the text was chosen accordingly: the first section addresses Christ and refers to his sacrifice on the Cross, while the second explicitly addresses Christ’s blood (‘O sanguis Christi’) flowing from the cross, and its healing powers. Lastly a short prayer asks God to wipe out sins and open the doors of the blissful realms (‘regna beata’) to sinners.
The first text is a short prayer^[1] that can be found in connection with the liturgical moment of the Elevation in books of hours, sometimes alone, sometimes accompanied by other prayers (e.g. in a book of hours from Naples now in Nuremberg, Germanisches Nationalmuseum, MS 22402, where this prayer is preceded by Ave domine Iesu Christe verbum patris) and sometimes introduced by a rubric such as: ‘Say [this prayer] humbly and inclined, while you beat your breast at the elevation of the body of the most holy Jesus our Lord’ (‘In elevatione corporis sanctissimi DNIC humiliter inclinatus percutiendo pectus tuum dic’) as transmitted in another fifteenth-century book of hours from Lille (Lille, Bibl. municipale, MS 14 [a.c.69]), or: ‘Say this devoutly when the body of Christ is elevated’ (‘Quando corpus domini elevatur devote dicas’), as in a fifteenth-century miscellaneous manuscript for private devotion from Pavia (Milan, Bibl. Nazionale Braidense, MS AD IX 41), or simply ‘Prayer for the elevation of the host’ (Oratio in elevatione hostiae), as in the afore-mentioned book of hours from Naples now in Nuremberg.^[2]
For the second section of the motet, the designer of the text chose the second and final part of the hexametrical prayer already used for the fifth motet of the cycle (the motet ‘loco Sanctus’). The text thematizes the blood of Christ and can thus be directely referred to the Elevation or Eucharist.

^[1] See Agnese Pavanello, ‘The Elevation as Liturgical Climax in Gesture and Sound: Milanese Elevation Motets in Context’, Journal of the Alamire Foundation, 9, no. 1 (2017), 33–59.

^[2] For all these concordances, see Giacomo Baroffio, ‘Corpus italicum precum: Materiali per una storia del sentimento religioso in Italia’, http://www.hymnos.sardegna.it/iter/iterliturgicum.htm.