It is Necessary for the Orthodox to Partake Frequently of the Divine Body and Blood of our Lord
All Orthodox Christians are commanded to receive Communion frequently.
First, by the orders of our Lord and Master Jesus Christ. Second, by the Acts and Canons of the Holy Apostles and the sacred Councils and the testimonies of the divine Fathers. Third, by the very words, the order, and the celebration of the Divine Liturgy. Fourth, by Holy Communion in and of itself.

By the Order of our Lord Jesus Christ
Our Lord Jesus Christ, before He handed down the Mystery of Communion, said: “And the bread that I will give is My flesh, which I will give for the life of the world.” (Jn 6:51).
This means that, for the faithful, divine Communion is a necessary constituent of the spiritual life in Christ....
In another place the Lord says imperatively: “Most assuredly, I say to you, unless you eat the flesh of the Son of Man and drink His blood, you have no life in you” (Jn 6:53).

By Act and Canons of Holy Apostles, Sacred Councils, and divine Fathers
When the Lord handed down this Mystery to His disciples, He did not merely make a recommendation, saying: “Whoever wants to eat my body, and whoever wants to drink my blood...” Rather, He commandingly cried out: “Take, eat; this is My body” (Mt 26:26) and, “Drink of it, all of you, this is My blood” (Mt 26:27-28). That is “You must absolutely eat My body, and you must unfailingly drink of My blood.”
The Apostles... at the beginning of their preaching gathered together as soon as they could with all of the faithful in a hidden place.... The sacred Luke bears witness in the Acts of the Apostles.... “And they continued steadfastly in the Apostles’ doctrine, and in Communion, and in breaking of bread, and in prayer” (Acts 2:42).
For later Christians to keep this mandatory tradition..., they also wrote in their eighth Canon... “If anyone... does not receive Communion when the offering is made, let him declare the reason; and, if it is legitimate, let him be excused. But if he does not declare it, let him be excommunicated.”
In the ninth Canon they say: “Any of the faithful who enter in and listen to the Scriptures, but do not stay for the prayers and Holy Communion, are to be excommunicated....
Following the sacred Apostles, the Council of Antioch ratifies the above Canons, and adds:
Any who enter the Church of God and listen to the sacred Scriptures, but... turn away from the communion of the Eucharist... are to be cast out of the Church until they have made confession, and shown fruits of repentance, and made entreaty, and then they will be able to be forgiven.

By the Words, Order and Celebration of the Divine Liturgy
If we look carefully at the sacred Divine Liturgy, we will see that, from the beginning to the end, it has as its goal and reference the Communion of the gathered faithful Christians.... The priest holding the sacred chalice containing the life-giving body and blood, exits from the sanctuary and holds it up for all the people to see. He then calls them to divine Communion, shouting aloud: “With the fear of God, with faith and with love, draw near.”
After Communion... the people offer thanksgiving: “Let our mouths be filled with Thy Praise, O Lord... for Thou hast deemed us worthy to partake of Thy holy, immortal, and immaculate Mysteries.”....
The Cherubic Hymn... says that all of us... who chant the thrice-holy hymn to the life-giving Trinity, are to cast out from our intellect every concern and care of this life, because we are going to partake of and receive into our soul the King of all...
The Lord’s Prayer, which is recited after the transubstantiation of the Mysteries, ...Christians ask from God the Father to give them the superessential bread, which is primarily Holy Communion....
Saint John Chrysostom says, “Suppose someone was invited to a feast, and was to wash his hands, and sit down, and be all ready at the table, and after that, refuse to partake. Is he not insulting the man who invited Him?... He (God) has invited us to heaven, to the Table of the great and wonderful King, and do we shrink and hesitate, instead of hastening and running to it? And what then is our hope of salvation? We cannot lay the blame on our weakness; we cannot lay it on our nature. It is laziness and nothing else that renders us unworthy.”

By Holy Communion In and Of Itself
Even divine communion in and of itself makes it imperative to partake of it frequently simply because... frequent communion is necessary for the life of the soul....
Basil the Great says: “The receiving of the body and blood of Christ is necessary for eternal life.” “He who has been reborn through Baptism must now be nourished by partaking of the divine Mysteries.... therefore, we are now nourished with the food of eternal life, which the Son of the living God handed down to us.” “It is good and beneficial to commune every day, and to partake of the holy body and blood of Christ, Who clearly says: ‘Whoso eateth My flesh, and drinketh My blood, hath eternal life’ (Jn 6:54).
Patriarch Gennadios of Constantinople says the following:
The Mystery brings about in those who partake of it progress in the life according to Christ... For the body of Christ nourishes and refreshes our soul, just as bread does for the body. ...with the Mystery of Communion we are straightened, and we remain and progress in grace. ...the heat of evil which gnaws away at the soul by drying out the quality of piety, would certainly destroy it completely if the soul did not receive spiritual food... The Body of Christ... since it is united to the divine Nature, purifies and sanctifies those who receive communion, and grants to us sufficient spiritual nourishment...

Since we have demonstrated from these testimonies that frequent Communion is necessary for those Christians (Who do not have a impediment), we also, then, have life, which is Jesus Christ, in ourselves, and so that we do not die a spiritual death. For as many as are not frequently nourished by that spiritual food will most surely die. Even if it appears that they are physically alive, they are spiritually dead, because they have distanced themselves from the spiritual and true life brought about by Holy Communion.

Saint Nikodemos the Hagiorite in Concerning Frequent Communion of the Immaculate Mysteries of Christ.