The ordination of men as priests or deacons can occur at any time. In the Western tradition, the Ember Days of Advent, Lent, September—and most especially the week of Pentecost—are designated for conferring the Sacrament of Holy Orders.
During these days, the entire Church joins the candidates in a special fast and penitential Mass on the Wednesday, Friday, and Saturday leading up to the ordination. At this time, they pray for the Spirit’s grace both upon the men who will be ordained, and upon the whole church so that she may increase and her members may grow in faith and holiness. Our Lord’s Church cannot grow in faith or holiness without His sacred ministers. Their ministry is to deliver His gifts—the sacred mysteries—which unite us to Christ, seal us with His Spirit, heal our bodies and forgive our souls, and strengthens our life in and with each other until we together attain the fullness of the kingdom of heaven.
But there is something more that is revealed in this Ember Day practice. The whole Christian community fasts and prays (while only some are being ordained) because this Holy Sacrament—unlike all the sacred mysteries—centers the Christian parish family. That is the essence of this sacrament. Fr Alexander Schmemann, of blessed memory, puts it this way:
If each man [or woman] is to find in Christ his own life, if Christian engineers find in the Church what it means to be a Christian engineer, if a Christian novelist finds in the church the idea of what is Christian art, if a Christian father and a Christian mother find in the Church the essence of Christian parenthood, there must be someone in the center of the community who, just as Christ, has nothing of his own, but in whom and through whom everyone else can find his way.
In practical terms, this means that the priest is the one who re-presents Christ; that is, who repeatedly makes Christ present. And it is the same with the deacon: he also presents Christ again and again.
The significant difference between the priest and deacon is that the priest’s primary focus is making present Christ’s compassion and mercy for the soul (i.e., through the sacraments and visitations), while the deacon’s primary emphasis is making present Christ’s compassion for the body (i.e., through material assistance and prayer).
These roles are clearly demonstrated in the Divine Liturgy: both when the deacon reads the Gospel, and when the priest dispenses the Eucharist, leads the prayers, and gives the blessing. In these instances, the deacon and priest first proclaim “Christ is in our midst” (“The Lord be with you”) before exercising their specific ministry. And the faithful acknowledge this whenever they respond, “And with thy spirit”—that is, and with the Spirit who was given to you in the Sacrament of Holy Orders.
Likewise, the Sacrament of Holy Orders is exactly that: a re-ordering of the life of the ordained man. No longer does that man have a “private” or “individual” life. No longer can he make decisions based solely on what is best for himself, his health, his prosperity or success, or even his family. And no longer can he set aside, even when “vacationing” or on his “day-off,” his duty and responsibility to serve at the altar or pray the prescribed prayers.
In a very real sense, then, the ordained man is “under orders.” In every moment, he must “become all things to all men.” He must “do good unto all men, especially unto them who are of the household of faith.” For his life is no longer his own, but is offered up as Christ gave Himself completely as a self-offering for men.
This is why Holy Orders is a sacrament which conveys the grace to bolster and sustain those who are ordained. And perhaps you see why it is both good and necessary for the whole Church to join in the fasts and prayers—not only for the men who will be ordained, but even more so for the priests and deacons who now serve. For by your fasting, you remember the sacrifice; and by your prayers, you support and encourage them in being faithful to their orders.