In the ancient sacrifices, both Jewish and pagan, those who took part were given part of the meat of the sacrificed animal, in the hope of a sort of communion with the divinity. In the Mass, after the sacrifice itself is completed, we have the unspeakable privilege of receiving the flesh and blood of the Divine Victim, who is not dead, but living, and comes to give life in abundance to our souls.
This Holy Communion, if we are rightly disposed, produces an increase in sanctifying grace - the ability to take in the vision of God in the life to come - plus a special claim to actual graces as needed, forgiveness of venial sin for which one is repentant, help to keep from mortal sin, and an increase in the virtue of love.
But dispositions are needed, for even though the Eucharist contains the very Author of all grace, it does not operate like magic: we must do what we can.
We must of course have the state of grace. Without it it would be sacrilege, and an added mortal sin to receive. Right intention is also needed, i.e., to please God, to be more closely united with Him, to gain a remedy for our weaknesses.
It is not required to be free from all venial sin. The reception itself may forgive venial sins for which one is sorry. But the fruits of receiving are reduced. It is especially needed that one be free from all deliberate venial sin - in contrast to sins of weakness, sins when one is taken off guard.
For fullest benefits, we should be free from all attachment to anything sinful. Some have as it were a gap in their purpose of amendment, as if they said, for example: "I do not intend to commit mortal sins, nor all venial sins. But there are some reservations: if it is hard to stick to the truth, I will not do so, or if it is hard to keep a conversation going without a bit of detraction, that is all right too. These dispositions, sometimes called "affection to venial sin" impose as it were a clamp on one's heart, for he/she has decided to go so far and no farther. So they effectively prevent spiritual growth beyond a certain point. How sad that many who could grow much, block growth by this means.
But mere carelessness, lack of preparation, or lack of thanksgiving can be harmful. Pope John Paul II, in his very first Encyclical, Redemptor hominis #20, said that if one does not constantly try to grow spiritually, receiving the Eucharist would "lack its full redeeming effectiveness" and there could even be a spiritual loss. To receive out of mere routine, with no special care, no thanksgiving, is more apt to cause spiritual loss than gain.
To prepare, one should think in advance about what he/she is going to do, especially during the Mass. After receiving, it is valuable to try for recollection, in humility to adore the Lord present we adore the Lord present within us, to give thanks, to express sorrow for deficiencies, to ask for helps to do better. It is very good to stay a few minutes after the end of the Mass to continue this thanksgiving.
Of course one should be decently dressed to receive. Some give scandal and lead others into sin in the very act of coming.
The Eucharistic fast has now been reduced to one hour - abstaining from food and drink (except water). The time is computed up to the actual time of reception. The sick, even if not confined to bed, and those actually engaged in caring for them at the time, need not observe any period of fasting. The same applies to the elderly, according to the new Code of Canon Law # 919. 3.
Children should begin to receive when they have reached the use of reason, but not before they have made their first confession. Once one has begun to receive, there is the obligation of receiving at least once a year, at Easter time, unless there is a reasonable cause for using a different time.
Pastors should see to it that the sick can receive at times. Those who are in danger of death are obliged to receive the Sacred Host as Viaticum, which means provision for the journey -into the next life.
The present law allows quite a few occasions when the Holy Eucharist may be received under both species. However, Christ is received whole and entire under one form only, for He dies no more: body and blood are never separated. (Cf. First Corinthians 11. 26-27, noting that in v. 26, the word and shows that both species are needed to express the death of the Lord, but for Holy Communion, only one species is needed. Hence the word or is used in v. 27).
When actual reception is not possible, one may profitably make a spiritual communion, by a fervent desire to receive sacramentally. This keeps the soul united with Jesus during the day, and prepares better for the actual reception.
Taken from A Basic Catholic Catechism (c) 1990 by Fr. William G. Most, Part 12.
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Related Q and A
366. What is Holy Communion?
Holy Communion is the receiving of Jesus Christ in the sacrament of the Holy Eucharist.
(a) Just as it is necessary to nourish our bodies with material food, so also it is necessary to nourish our souls with spiritual food. Our Divine Savior so loved us that He gave us Himself in the sacrament of the Holy Eucharist; He gave us His own body and blood as food for our souls.
(b) It is not necessary that we receive Our Lord's body and blood under the appearances of both bread and wine. Christ is entirely present under the appearances of bread, and also entirely present under the appearances of wine. Therefore, we receive Him whole and entire under the appearances of bread alone or of wine alone.
(c) In some Eastern Churches the faithful receive Holy Communion under the appearances of both bread and wine. In the Western Church the faithful receive Communion most commonly under the appearances of bread, with the Precious Blood generally reserved by law to special feasts or other particular circumstances.
367. What is necessary to receive Holy Communion worthily?
To receive Holy Communion worthily it is necessary to be free from mortal sin, to have a right intention and to obey the Church's laws on the fast required before Holy Communion out of reverence for the body and blood of Our Divine Lord. However, these are some cases in which Holy Communion may be received without fasting.
(a) Venial sin does not make us unworthy of receiving Holy Communion; but it does prevent us from receiving the more abundant graces and blessings which we would otherwise receive from Holy Communion.
368. Does he who knowingly receives Holy Communion in mortal sin receive the body and blood of Christ and His graces?
He who knowingly receives Holy Communion in mortal sin receives the body and blood of Christ, but he does not receive His graces and commits a grave sin of sacrilege.
(a) To receive Holy Communion unworthily is a serious abuse of the sacred body and blood of the Lord, and therefore a sacrilege.
369. What should we do to receive more abundantly the graces of Holy Communion?
To receive more abundantly the graces of Holy Communion we should strive to be most fervent and to free ourselves from deliberate venial sin.
370, What are the current rules for fasting before Holy Communion?
(a) For many centuries the Church commanded a strict fast from midnight before one could receive Holy Communion. However, in the 1950's Pope Pius XII introduced a much more lenient form of fasting before Holy Communion in order to give Catholics an opportunity to receive Holy Communion more frequently.
(b) Pope Pius XII also allowed the celebration of afternoon and evening Masses every day, when the spiritual good of a considerable number of the faithful requires it. It is the right of the bishop of each diocese to decide when such Masses may be offered in his diocese.
(c) Paul VI further reduced the fasting requirement after the Second Vatican Council, requiring only a one hour fast from all food and drink (excluding water). This may be reduced to 15 minutes for those who are sick or for other important reasons. This is the practice currently in force.
371. When may Holy Communion be received without fasting?
Holy Communion may be received without fasting when one is in danger of death, or when it is necessary to save the Blessed Sacrament from insult or injury.
(a) Ordinarily the danger of death comes from sickness or injury. But it is not necessary that a person be in danger of death from sickness in order to receive Holy Communion without fasting. The danger of death may come from some other cause. A soldier, for example, who is about to go into battle or a person about to be executed may receive Holy Communion without fasting.
373. How should we prepare ourselves for Holy Communion?
We should prepare ourselves for Holy Communion by thinking of Our Divine Redeemer whom we are about to receive, and by making fervent acts of faith, hope, love, and contrition.
(a) We should be neat, clean, and modest in our appearance, and respectful and reverent in our manner.
(b) Each time we receive Holy Communion we should try to be as devout and fervent as if it were the only Communion of our lives.
374. What should we do after Holy Communion?
After Holy Communion we should spend some time adoring Our Lord, thanking Him, renewing our promises of love and of obedience to Him, and asking Him for blessings for ourselves and others.
375. What are the chief effects of a worthy Holy Communion?
The chief effects of a worthy Holy Communion are:
first, a closer union with Our Lord and a more fervent love of God and of our neighbor;
second, an increase of sanctifying grace;
third, preservation from mortal sin the and remission of venial sin;
fourth, the lessening of our inclinations to sin and the help to practice good works.
376. When are we obliged to receive Holy Communion?
We are obliged to receive Holy Communion during Easter time each year and when in danger of death.
377. Why is it well to receive Holy Communion often, even daily?
It is well to receive Holy Communion often, even daily, because this intimate union with Jesus Christ, the Source of all holiness and the Giver of all graces, is the greatest aid to holy life.
378. How should we show our gratitude to Our Lord for remaining always on our altars in the Holy Eucharist?
We should show our gratitude to Our Lord for remaining always on our altars in the Holy Eucharist, by visiting Him often, by reverence in church, by assisting every day at Mass when this is possible, by attending parish devotions, and by being present at Benediction of the Blessed Sacrament.
(a) Benediction of the Blessed Sacrament is a ceremony in which the sacred host is exposed for a time on the altar, usually in the monstrance. During Benediction the priest blesses the people with the sacred host.
(b) The monstrance, or ostensorium, is a large vessel in which the host is exposed to view through a glass-covered opening in the center.
(c) The long cloak-like vestment worn by the priest at Benediction of the Blessed Sacrament is called a cope. The humeral veil is placed over the priest's shoulders before he gives the blessing.
Modified slightly from The Baltimore Catechism, Lesson 28.
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