The hora sexta of the Romans corresponded closely with our noon. Among the Jews it was already regarded, together with Terce and None, as an hour most favourable to prayer. In the Acts of the Apostles we read that St. Peter went up to the higher parts of the house to pray (). It was the middle of the day, also the usual hour of rest, and in consequence for devout men, an occasion to pray to God, as were the morning and evening hours.
The Fathers of the Church dwell constantly on the symbolism of this hour; their teaching is merely summarized here: it is treated at length in Cardinal Bona's work on psalmody. Noon is the hour when the sun is at its full, it is the image of Divine splendour, the plenitude of God, the time of grace; at the sixth hour Abraham received the three angels, the image of the Trinity; at the sixth hour Adam and Eve ate the fatal apple. We should pray at noon, says St. Ambrose, because that is the time when the Divine light is in its fulness. Origen, St. Augustine, and several others regard this hour as favourable to prayer. Lastly and above all, it was the hour when Christ was nailed to the Cross; this memory excelling all the others left a still visible trace in most of the liturgy of this hour.
All these mystic reasons and traditions, which indicate the sixth hour as a culminating point in the day, a sort of pause in the life of affairs, the hour of repast, could not but exercise an influence on Christians, inducing them to choose it as an hour of prayer. As early as the third century the hour of Sext was considered as important as Terce and None as an hour of prayer. Clement of Alexandria speaks of these three hours of prayer, as does Tertullian. Long previous the Didache had spoken of the sixth hour in the same manner. Origen, the "Canons of Hippolytus", and St. Cyprian express the same tradition. It is therefore evident that the custom of prayer at the sixth hour was well-established in the 3rd century and even in the 2nd century or at the end of the 1st century. But probably most of these texts refer to private prayer. In the 4th century the hour of Sext was widely established as a Canonical Hour. The following are very explicit examples. In his rule St. Basil made the sixth hour an hour of prayer for the monks,, St. John Cassian treats it as an hour of prayer generally recognized in his monasteries The De virginitate, wrongly attributed to St. Athanasius, but in any case dating from the fourth century, speaks of the prayer of Sext, as do also the "Apostolic Constitutions", St. Ephrem, St. John Chrysostom But this does not prove that the observance of Sext, any more than Prime, Terce, None, or even the other Canonical Hours, was universal. Discipline on this point varied widely according to regions and Churches. And in fact some countries may be mentioned where the custom was introduced only later. That the same variety prevailed in the formulæ of prayer is shown in the following paragraph.
Despite its antiquity the hour of Sext never had the importance of those of Vigils, Matins, and Vespers. It must have been of short duration. The oldest testimonies mentioned seem to refer to a short prayer of a private nature. In the fourth and the following centuries the texts which speak of the compositions of this Office are far from uniform. John Cassian tells us that in Palestine three psalms were recited for Sext, as also for Terce and None This number was adopted by the Rules of St. Benedict, St. Columbanus, St. Isidore, St. Fructuosus, and to a certain extent by the Roman Church. However, Cassian says that in some provinces three psalms were said at Terce, six at Sext, and nine at None. Others recited six psalms at each hour and this custom became general among the Gauls. In Martène will be found the proof of variations in different Churches and monasteries. With regard to ancient times the Peregrinatio Sylviæ, tells us that at the hour of Sext all assembled in the Anastasis where psalms and anthems were recited, after which the bishop came and blessed the people. The number of psalms is not stated.
In the sixth century the Rule of St. Benedict gives the detailed composition of this Office. We quote it here because it is almost the same as the Roman Liturgy; either the latter borrowed from St. Benedict, or St. Benedict was inspired by the Roman usage. Sext, like Terce and None, was composed at most of three psalms, of which the choice was fixed, the Deus in adjutorium, a hymn, a lesson (capitulum), a versicle, the Kyrie Eleison, and the customary concluding prayer and dismissal
In the Roman liturgy Sext is also composed of the Deus in adjutorium, a hymn, three portions of Psalm 118, the lesson, the short response, the versicle, and the prayer. (For the Byzantine Rite, see Eastern Christian Office, below.) In the modern Mozarabic Office Sext consists only of Ps. 53, three "octonaries" of Psalm 118, two lessons, the hymn, the supplication, the capitulum, the Pater Noster, and the benediction.
In the Eastern Orthodox and Greek Catholic Churches the office of the Sixth Hour is normally read by a single Reader and has very little variation in it. Three fixed psalms are read at the Third Hour: Psalms 53, 54 and 90 (LXX). The only variable portions for most of the year are the Troparia (either one or two) and Kontakion of the Day.
During Great Lent a number of changes in the office take place. On Monday through Friday, after the three fixed psalms, the Reader says a kathisma from the Psalter. The Troparion of the Day is replaced by special Lenten hymns that are chanted with prostrations. Then, a special Troparion of the Prophesy is chanted, which is particular to that specific day of Great Lent. This is followed by a Prokeimenon, a reading from Isaiah and another Prokeimenon. Then there may follow a reading from the Ladder of Divine Ascent. The Kontakion of the Day is replaced by special Lenten troparia. Near the end of the Hour, the Prayer of St. Ephraim is said, with prostrations.
During Holy Week, on Great Monday, Tuesday and Wednesday, the services are similar to those during Great Lent (including the reading of a kathisma), but instead of the normal Lenten hymns which replace the Kontakion, the Kontakion of the day (i.e., that day of Holy Week) is chanted. On Great Thursday and Saturday, the Little Hours are more like normal. On Great Friday, the Royal Hours are chanted.
During the Lesser Lenten seasons (Nativity Fast, Apostles' Fast and Dormition Fast) the Little Hours undergo changes similar to those during Great Lent, except the Lenten hymns are usually read instead of chanted, and there are no kathismata. In addition, on weekdays of the Lesser Fasts, an Inter-Hour (Greek: Mesorion) may be read immediately after each Hour (at least on the first day of the Fast). The Inter-Hours may also be read during Great Lent if there is to be no reading from the Ladder of Divine Ascent at the Little Hours. The Inter-Hours follow the same general outline as the Little Hours, except they are shorter.
, s.v., Sext