Here, as briefly as possible, some expressions and words of the canons are explained, which custom prescribes to be read in preparation for Holy Communion.
On the eve of communion, you need to read at home, in addition to the usual prayers for the future, the canon of repentance, the canons of the Mother of God and the Guardian Angel. The canons are read either one after the other in full, or by combining them in the same way as the canons are combined during the divine service, when reading in church at Matins: the irmos of the first song of the penitential canon “Like on dry ground...” and the troparia (with choruses) are read or sung, then the troparia of the first song of the canon to the Mother of God “We contain many misfortunes...”, omitting the irmos “Water has passed...”, and the troparia canon to the Guardian Angel, also without the irmos “Let us drink to the Lord...”. The following songs are read in the same way. The troparia before the canons of the Theotokos and the Guardian Angel, as well as the stichera after the canon of the Theotokos, are omitted in this case.
Here are the three canons that are given in most prayer books, but there are also other penitential canons and canons to the Most Holy Theotokos. When preparing for communion on the eve of great holidays (after the festive all-night vigil), it is possible, and sometimes even desirable, to replace these canons with the canon of the holiday from the Festive Menaion (it would be good if it was possible not only to omit the canons below, but to transfer their reading to the previous days of the fast). When reading the canons and akathists, do not forget about the usual beginning and end of any prayer order.
A few words about the canon - a complex and spiritually rich form of church poetry. The Canon always compares Old Testament types and prophecies with corresponding events in the New Testament. The complete canon consists of nine songs (and each song consists of an irmos and similar troparions following it); in this very nine-part composition there is deep praise for the Most Holy Trinity: three times three songs. The penultimate troparion of each song of the canon praised the Most Holy Trinity and was called Trinity (We find Trinity canons in the most ancient canons and compiled according to their models; in later times they ceased to be obligatory), and the last one is dedicated to the glorification of the Most Holy Theotokos.
Historically, in the vast majority of canons, the 2nd canto is absent, so the 1st canto is immediately followed by the 3rd.
Irmos is the model according to which the rest of the troparia of this song are compiled; it is the irmos that points to the Old Testament prototypes, and the content of the irmos of each song of the canon is based on certain passages of Holy Scripture - the so-called biblical songs (which texts of the Holy Scripture are the basis for the biblical songs, and after them the irmos, are indicated below). The troparia following the Irmos are consistent with it in content, poetic form, and rhythm; in ancient times, the troparia of the canon were sung, like the irmos, to the same melody. Now the irmos is sung, and other troparia are read (however, the tradition of singing the entire canon of prayer to the Most Holy Theotokos given below has also been preserved). In private use, of course, you can also read irmos (you should be guided by which performance will be more prayerful and focused for you).
The poetic form of the canon especially clearly captures the Orthodox perception of the world: the Old Testament is perceived through the prism of the New Testament, and in this double light, the Old and New Testaments, the entire universe appears. The passage of Israel through the Red Sea, the cry of Jonah from the belly of the whale, the triumphant song of the youths thrown into the fiery furnace and not scorched by fire - all this, thanks to the canon, becomes the most important fact of the life of every Orthodox Christian, deeply personally experienced and connected with his worldview and his entire inner life.
The melody of the canon obeys one of eight voices. It is not difficult to remember the melody of common Irmos if you often attend Matins services (for example, as part of an all-night vigil): it is the performance of the canon that is the liturgical center of Matins.
The reading of each troparion of the canon is preceded by a chorus - a short prayer appeal. Usually the chorus is read rather than sung.