On which days to commemorate the reposed?

The Church's Prayer for the Dead

At every Divine Service, the Holy Orthodox Church offers up prayers for her departed children. Special prayers and Troparia are read at Compline (Night Service) and Nocturns (Midnight Service), and at Vespers and Matins the departed are remembered in the Litany of Fervent Supplication. At the Divine Liturgy the departed are commemorated at the Proskomedia, in the Litany following the Gospel and when It is truly meet... is sung. In addition, it is customary to have a Service for the departed on Saturdays, unless this coincides with a feast on that day.

The Third Day

On the third day after death, it is customary to commemorate the departed, since they had been baptized in the Name of the Holy Trinity-Father, Son and Holy Spirit and had kept the Orthodox Faith they received at Holy Baptism. In addition, as the Apostolic Constitutions point out: Let the third day of the departed be celebrated with psalms and lessons, and prayers, on account of Him Who arose within the space of three days (Bk. 8, Ch. 42], that is, in honor of the Third-Day Resurrection of our Lord Jesus Christ.

The Ninth Day

On the ninth day after death, the Orthodox Church offers prayers for the departed both in remembrance of the living [Apost. Const.} and that the departed soul be counted worthy to be numbered among the choir of the saints, through the prayers and intercessions of the nine ranks of angels.

The Fortieth Day

From earliest times the Church had commanded that the departed be commemorated during the course of forty days and on the fortieth day itself, for so did the people lament Moses after his death [Apost. Const.]. This is also done in remembrance of the victory of Christ over Satan after He had spent forty days in fasting and prayer. The Church also commemorates the departed on the yearly anniversary of death and, in some places, on the twentieth day, and the third, sixth and ninth months, as well. It is also customary to commemorate the departed on their birthdays and patronal saint's days.

Koliva (grain or rice, cooked with honey or sugar, sometimes mixed with plums, raisins and other sweets) is often offered on these days of commemoration. The grain and fruit signify that the dead will again rise from the grave by God's might, for both the grain (sown in the ground) and the fruit (which falls on the ground) decay first and then afterwards bring forth abundant, ripe and whole fruit. Sugar and honey signify that after the Resurrection of the righteous, there will come a joyful and blessed life n the Kingdom of Heaven, rather than one bitter and sorrowful.

As St. Simeon of Thessalonica says: The [Third Day Service] is celebrated for the reason that [the departed one] received his being through the Trinity and having passed to a state of good being and being changed he shall [at the Resurrection] appear in his original state or one superior. The [Ninth Day] is celebrated that his spirit dwell together with the holy spirits the angels being immaterial and naturally similar to them for these spirits are nine in number and by them [the orders] they triply proclaim and praise the God in Trinity and so that he may be united with the holy spirits of the Saints. The [Fortieth Day] is celebrated because of the Savior's Ascension which came to pass after so many days after His Resurrection in the sense that [the reposed], as it were, having also risen and having ascended...being caught away in the clouds, shall meet the Judge and thus being united with Him, he should ever be with the Lord (1 Thess. 4:17).

Now the third, sixth and ninth months are also celebrated as proclaiming the Trinity, the God of all, and to His glory in behalf of the deceased, for by the Trinity a man is fashioned, and when loosed from the body he returns to Him, and by the Trinity he hopes to receive resurrection. But the end of the year is celebrated because it is the consummation, and our God, the Trinity, is the Life of all and the Cause of being, and shall be the Restoration of all and the Renewal of human nature [On Things Done for the Departed].

In general, the custom of observing prayers for the dead has been held by the Orthodox Church since earliest times. The Divine Liturgy has always been celebrated in memory of the departed and, on these days, many have increased and continue to increase their offerings in the Church, assisting the poor and needy brethren out of love for their departed loved ones.

In addition to these personal days for remembrance of the departed, the Church has also set aside a number of universal days of commemoration. These are:

Meatfare Sunday

This Saturday falls during Meatfare Week, which is the last week for eating meat before the start of the Great Fast. On the following day, Meatfare Sunday, the Church commemorates the Dread Judgment of Christ, and for this reason, on the Saturday before she prays for all who have departed in faith and hope of Resurrection, that Christ show mercy to them at the Universal Judgment. This commemoration dates from very ancient times and here the Church especially prays for those who have met untimely deaths and have been left without a proper funeral. This is evident from the hymns of that day, including the following from the Matins Canon:

To those hidden by the deep or cut down in battle, swallowed by earthquake, murdered, or consumed by fire, grant in Thy mercy a place with the faithful and the righteous [Ode 1].

Those whom the creatures of the sea or the birds of the air have devoured, O Christ our God, raise up in glory on the Last Day, as Thou judgest right [Ode 3].

Give rest, O Christ, to all the faithful destroyed by the wrath of God: struck down by deadly thunderbolts from heaven, swallowed by a cleft in the earth, or drowned in the sea [Ode 9].

Second, Third and Fourth Saturdays of Great Lent.

Since the usual Divine Liturgy of St. John Chrysostom is not celebrated on the weekdays of Great Lent, but rather the Liturgy of the Presanctified Gifts, it is the accepted custom of the Church to commemorate the dead on these three Saturdays (the other Saturdays being dedicated to special celebrations: St. Theodore on the 1st Saturday, the Akathist to the Theotokos on the 5th, and the Resurrection of Lazarus on the 6th), so that the dead not be deprived of the Church's saving intercession.

Tuesday of St. Thomas Week

According to pious custom, a commemoration of the dead is made so that, having celebrated the bright festival of Christ's Resurrection, the joy of the Paschal feast be shared with those that have departed in the hope of their own Resurrection. Thus this day bears the name, Day of Rejoicing (Radonitsa).

Trinity Saturday

On this day (the Saturday before Holy Pentecost) the Church asks that the saving grace of the Holy Spirit wash away the sins from the souls of all our forefathers, fathers and brethren that have reposed from all the ages, asking that they all be united in the Kingdom of Heaven.

Commemoration of Departed Orthodox Warriors

The Church has also set aside two days of remembrance for those who have laid down their lives in battle:

Beheading of St. John the Baptist (Aug. 29)

On the day of the Beheading of the Prophet, Forerunner and Baptist of the Lord, the Church prays for all who have died for faith and homeland, as being like the righteous John who suffered for the truth.

St. Demetrius Saturday (Sat. before Oct. 26)

This commemoration was originally initiated by Great Prince Dimitry Donskoy on his Patron Saint's Day (St. Demetrius of Thessalonica Oct. 26) in 1380. In remembrance of his great victory over the Tatars on Kulikovo Field (in the present-day Province of Tula in Russia), Prince Dimitry made a pilgrimage to the Trinity-Sergius Monastery at Zagorsk (Sergiev Posad) (near Moscow). After commemorating all who fell in that war, he later decreed that the annual remembrance be made on the Saturday before October 26. Later, Orthodox Christians began to commemorate on this day, not only Orthodox warriors fallen for the Faith, but also for all Orthodox Christians who have died in the Faith.

The Jesus Prayer Prayer of the Heart

For the Orthodox, the prayer par excellence is the Jesus Prayer, Lord Jesus Christ, Son of God, have mercy on me a sinner (or, in its shorter form, Jesus, Son of God, have mercy on me). From New Testament times, the Orthodox have believed that the power of God is present in the Name of Jesus. When the Apostle Peter healed a crippled man at the Beautiful Gate of the Temple, he was questioned by the High Priest: By what power or by what name did you do this? (Acts 4:7). St. Peter, filled with the Holy Spirit, answered: Be it known to you all, and to all the people of Israel, that by the Name of Jesus Christ of Nazareth, Whom you crucified, Whom God raised from the dead, by Him this man is standing before you well (Acts 4:10).

Our Lord Himself, comforting His disciples before His passion and death, told them that Whatever you ask in My Name, I will do it, that the Father may be glorified in the Son; if you ask anything in My Name, I will do it (John 14:13-14). Truly, truly, I say to you, if you ask anything of the Father, He will give it to you in My Name. Hitherto you have asked nothing in My Name; ask and you will receive, that your joy may be full (John 16:23-24).

Later, in the era immediately following the time of the Apostles, St. Ignatius of Antioch (who had known St. John the Evangelist), when he was being led into the arena in Rome to suffer martyrdom by wild beasts, when he was asked by the soldiers guarding him why he kept repeating the name Jesus unceasingly, replied that It was written in his heart.

Thus, praying this prayer in the Name of Jesus Christ has been a vital part of the Orthodox spiritual tradition from earliest times and has been especially treasured by monastics since the 4th Century. In the Service for the Tonsuring of a Monk, when he is given the Prayer Rope (Komvoschoinlon Chotki), the Abbot says, as it is handed over: Take, brother, the sword of the Spirit, which is the Word of God, for continual prayer to Jesus; for you must always have the Name of the Lord Jesus in mind, in heart, and on your lips, ever saying: 'Lord Jesus Christ, Son of God, have mercy on me, a sinner.'

However, while especially practiced and popularized by monastics, praying in the Name of Jesus is every bit the privilege of all Christians. As the Prayerbook says, At work and at rest, at home and on journeys, alone or among other people, always and everywhere repeat in your mind and heart the sweet name of the Lord Jesus Christ, saying: 'Lord Jesus Christ, Son of God, have mercy on me, a sinner.' In our busy lives, however, how can an ordinary Orthodox Christian practice this unceasing Prayer of Jesus?

In our daily affairs, there are many things that we do out of habit. At the beginning of the day, for example, we wash, we dress, we have breakfast, and so on. As we go on our way to work, there is usually much free time. During the working day, whether at home doing housework, or at the factory, shop or office, there are many idle moments or moments of repetitious work. Even in such recreational activities as hiking, jogging, or whatever, there are many opportunities to engage in prayer. And what better time to do good, to unceasingly call on the Name of Jesus, can there be than at times such as these? Even the most monotonous task can be transformed into a sweet and joyful experience!

Even if we are in a crowd, at work, at a family gathering, in situations that demand all our thought and attention, it is possible to say the Prayer of Jesus, perhaps not for long, continuous blocks of time, but from time to time. As Archbishop Paul, Primate of the Orthodox Church of Finland and a Valaam Monk states: If we get into the habit of reciting the Name of Jesus in this way even for half a minute at a time and it is possible to arrange such a pause for oneself in almost any work remembrance of God's presence will remain as an undercurrent in our soul. [This and other passages herein are taken from The Faith We Hold, by Archbishop Paul, p.85-86.]

The Jesus Prayer, then, is a prayer of amazing versatility; it is a prayer for beginners and equally a prayer that leads to the deepest mysteries of the contemplative life. For some, there comes a time when the Jesus Prayer enters into the heart, so to speak, which is why it is also called The Prayer of the Heart. At this point, the Jesus Prayer is no longer recited by means of a deliberate effort, but repeats itself spontaneously, continuing even when one talks or writes, is present in one's dreams and wakes him up in the morning.

Source: http://www.stots.edu/article.php?id=44