Chapter 23. On the veil of the sanctuary, when it is opened and when it is closed.
The veil is opened at the beginning of Vespers, and stays open until the dismissal. At Matins likewise, from the beginning to the end. At the Hours, when they are read apart from the Liturgy, the veil is opened for the reading of the Apostol* and stays open until the dismissal. It is closed after the dismissal. At the beginning of the Divine Liturgy the veil is opened and stays open until the Great Entrance. After the Entrance it is closed until the priest or deacon says: The doors! The doors! In wisdom let us attend. Then it is opened and stays open until the exclamation "Holy Things are for the holy." Then it is closed again. After the communion [of the clergy] the veil is opened again and stays open until the end of the Divine Liturgy. After the dismissal of the Liturgy it is closed again. When a molieben is sung the veil stays open from the beginning until the dismissal.
Let it be known that the Holy Doors are never opened except at the beginning of Great Vespers, when we have a Vigil, and the priest censes, and for all Entrances, that is, at Vespers and the Liturgy, and [for the reading of] the Holy Gospel. They are also opened from the moment the Holy Mysteries appear and until the end of the Divine Liturgy.
*Book of the Epistles and Acts.