Holy Communion

The reception and consumption of the sacrament of the Holy Eucharist or Blessed Sacrament whereby we participate in Christ Himself and in His Sacrificial work. All those who are baptized and have the requisite intention may receive Holy Communion (must do so at least once a year); they must be in a state of grace, and normally fasting from midnight, and fully to profit from the Sacrament must have dispositions of charity. (Definition from A Catholic Dictionary, 1951)

Surprisingly, many Catholics today either do not receive Holy Communion, do not receive it in the state of grace, and many do not even believe in the real presence! See references in Scripture and Church teaching below.
 

References in Scripture to the Real Presence in Holy Communion (and to receiving in the state of grace):

• "The chalice of benediction, which we bless, is it not the communion of the blood of Christ? And the bread, which we break, is it not the partaking of the body of the Lord?" 1 Corinthians 10:16
• "And whilst they were at supper, Jesus took bread, and blessed, and broke: and gave to his disciples, and said: Take ye, and eat. This is my body" Matthew 26:26
• "And taking bread, he gave thanks, and brake; and gave to them, saying: This is my body, which is given for you. Do this for a commemoration of me" Luke 22:19
• "If any man eat of this bread, he shall live for ever; and the bread that I will give, is my flesh, for the life of the world" John 6:52
• "And whilst they were eating, Jesus took bread; and blessing, broke, and gave to them, and said: Take ye. This is my body." Mark 14:22
• "I am the bread of life" John 6:48
• "This is the bread which cometh down from heaven; that if any man eat of it, he may not die. I am the living bread which came down from heaven" John 6:50-51
• "Then Jesus said to them: Amen, amen I say unto you: Except you eat the flesh of the Son of man, and drink his blood, you shall not have life in you. He that eateth my flesh, and drinketh my blood, hath everlasting life: and I will raise him up in the last day." John 6:54-55
• "For my flesh is meat indeed: and my blood is drink indeed. He that eateth my flesh, and drinketh my blood, abideth in me, and I in him" John 6:56-57
• "For as often as you shall eat this bread, and drink the chalice, you shall shew the death of the Lord, until he come. Therefore whosoever shall eat this bread, or drink the chalice of the Lord unworthily, shall be guilty of the body and of the blood of the Lord. But let a man prove himself: and so let him eat of that bread, and drink of the chalice. For he that eateth and drinketh unworthily, eateth and drinketh judgment to himself, not discerning the body of the Lord." 1 Corinthians 11:26-29
• "Then Jesus said to them: Amen, amen I say to you; Moses gave you not bread from heaven, but my Father giveth you the true bread from heaven. For the bread of God is that which cometh down from heaven, and giveth life to the world." John 6:32-33

Church Teaching on the Real Presence in the Eucharist:

• "...but that food which you receive, that living Bread which came down from heaven, furnishes the substance of eternal life; and whosoever shall eat of this Bread shall never die, and it is the Body of Christ. Now consider whether the bread of angels be more excellent or the Flesh of Christ, which is indeed the body of life" St. Ambrose, On the Mysteries, 4th century
• "When our Lord says: This is my body, this is my blood, no person of sound mind can mistake His meaning, particularly since there is reference to Christ's human nature, the reality of which the Catholic faith permits no one to doubt. The admirable words of St. Hilary, a man not less eminent for piety than learning, are apt here: When our Lord himself declares, as our faith teaches us, that His flesh is food indeed, what room can remain for doubt concerning the real presence of His body and blood?" Catechism of Council of Trent, The Sacrament of the Eucharist, The Mystery of the Real Presence
• "Another means of ascertaining the belief of the holy Church on matters of faith is the condemnation of the contrary doctrine and opinion. It is manifest that belief in the Real Presence of the body of Christ in the holy Sacrament of the Eucharist was so spread and taught throughout the universal Church and unanimously professed by all the faithful, that when, five centuries ago, Berengarius presumed to deny this dogma, asserting that the Eucharist was only a sign, he was unanimously condemned in the Council of Vercelli, which Leo IX had immediately convoked, whereupon he himself anathematised his error.
  Relapsing, however, into the same wicked folly, he was condemned by three different Councils, convened, one at Tours, the other two at Rome; of the two latter, one was summoned by Pope Nicholas II, the other by Pope Gregory VIII.' The General Council of Lateran, held under Innocent III, further ratified the sentence. Finally this truth was more clearly defined and established in the Councils of Florence and Trent" Catechism of Council of Trent, The Sacrament of the Eucharist, The Mystery of the Real Presence
• "In the first place, the holy Synod teaches, and openly and simply professes, that, in the august sacrament of the holy Eucharist, after the consecration of the bread and wine, our Lord Jesus Christ, true God and man, is truly, really, and substantially contained under the species of those sensible things" Council of Trent, On the real presence of our Lord Jesus Christ in the most holy sacrament of the Eucharist
• "Q: Why do you believe that in the Eucharist Jesus Christ is really present?
  A: I believe that in the Eucharist Jesus Christ is truly present, because He Himself has said it, and holy Church teaches it" Catechism of St. Pius X, The Blessed Eucharist
• "Some even say that the doctrine of transubstantiation, based on an antiquated philosophic notion of substance, should be so modified that the real presence of Christ in the Holy Eucharist be reduced to a kind of symbolism, whereby the consecrated species would be merely efficacious signs of the spiritual presence of Christ and of His intimate union with the faithful members of His Mystical Body....These and like errors, it is clear, have crept in among certain of Our sons who are deceived by imprudent zeal for souls or by false science. To them We are compelled with grief to repeat once again truths already well known, and to point out with solicitude clear errors and dangers of error" Encyclical Concerning Some False Opinions Threatening to Undermine The Foundations of Catholic Doctrine, 1950

Church Teaching on being in the state of grace to receive Holy Communion:

• "We should, in the next place, carefully examine whether our consciences be defiled by mortal sin, which has to be repented of, in order that it may be blotted out before Communion by the remedy of contrition and confession. The Council of Trent has defined that no one conscious of mortal sin and having an opportunity of going to confession, however contrite he may deem himself, is to approach the Holy Eucharist until he has been purified by sacramental confession." Catechism of Council of Trent - The Sacraments - The Eucharist
• "It is as impossible for the soul in the state of mortal sin to receive this Heavenly Bread with profit, as it is for a corpse to assimilate food and drink" Catholic Encyclopedia, 1917, The Blessed Eucharist as a Sacrament
• "The Apostle says (1 Cor. 11:29): "He that eateth and drinketh unworthily, eateth and drinketh judgment to himself." Now the gloss says on this passage: "He eats and drinks unworthily who is in sin, or who handles it irreverently." Therefore, if anyone, while in mortal sin, receives this sacrament, he purchases damnation, by sinning mortally".
  Further on we also read, "And therefore it is manifest that whoever receives this sacrament while in mortal sin, is guilty of lying to this sacrament, and consequently of sacrilege, because he profanes the sacrament: and therefore he sins mortally" Summa Theologica, Whether the sinner sins in receiving Christ's body sacramentally?
• "Q: What should one who knows that he is in mortal sin do before receiving Communion?
  A: One who knows that he is in mortal sin must make a good confession before going to Holy Communion, for even an act of perfect contrition is not enough without confession to enable one who is in mortal sin to receive Holy Communion properly." Catechism of St. Pius X, The Blessed Eucharist
• "Q: Does he who goes to Communion in mortal sin receive Jesus Christ?
  A: He who goes to Communion in mortal sin receives Jesus Christ but not His grace; moreover, he commits a sacrilege and renders himself deserving of sentence of damnation" Catechism of St. Pius X, The Blessed Eucharist
   

Church Teaching on the Eucharistic Fast:

• "Q: What sort of fast is required before Communion?
  A: Before communion there is required a natural fast which is broken by taking the least thing by way of food or drink" Catechism of St. Pius X, The Blessed Eucharist
• "Q: Is it ever allowed to go to Communion after having broken the fast?
  A: To go to Communion after having broken the fast is permitted to the sick, who are in danger of death, and to those who on account of prolonged illness have received a special dispensation from the Pope. Communion given to the sick in danger of death is called viaticum, because it supports them on their way from this life to eternity." Catechism of St. Pius X, The Blessed Eucharist
• "It is not, however, lawful to consecrate or partake of the Eucharist after eating or drinking, because, according to a custom wisely introduced by the Apostles, as ancient writers have recorded, and which has ever been retained and preserved, Communion is received only by persons who are fasting." Catechism of Council of Trent, The Sacrament of the Eucharist
• "It is sufficient to abstain for three hours from solid foods and alcoholic liquids and for one hour from non-alcoholic liquids. There is no longer any problem of morning or evening, of distances to be traveled to get to church, nor of strenuous labor or late hours" Encyclical On Laws of Fasting and the Evening Mass by Pope Pius XII, 1957
   

Church Teaching on properly receiving Holy Communion:

• "Q: How should we act while receiving Holy Communion?
  A: In the act of receiving Holy Communion we should be kneeling, hold our head slightly raised, our eyes modest and fixed on the sacred Host, our mouth sufficiently open, and the tongue slightly out over the lips" Catechism of St. Pius X, The Blessed Eucharist

Catholic Church Teaching on Easter Duty (Church requirement to receive Communion at least annually):

• "Paschal Tide is the period during which every member of the faithful who has attained the year of discretion is bound by the positive law of the Church to receive Holy Communion (Easter duty). During the early Middle Ages from the time of the Synod of Agde (508), it was customary to receive Holy Communion at least three times a year -- Christmas, Easter, and Pentecost. A positive precept was issued by the Fourth Lateran Council (1215) and confirmed by the Council of Trent (Sess. XIII, can. ix). According to these decrees the faithful of either sex, after coming to the age of discretion, must receive at least at Easter the Sacrament of the Eucharist (unless by the advice of the parish priest they abstain for a while). Otherwise during life they are to be prevented from entering the church and when dead are to be denied Christian burial."
  Catholic Encyclopedia, 1917, Paschal Tide
• "Lest any be kept away from Communion by the fear that the requisite preparation is too hard and laborious, the faithful are frequently to be reminded that they are all bound to receive the Holy Eucharist. Furthermore, the Church has decreed that whoever neglects to approach Holy Communion once a year, at Easter, is liable to sentence of excommunication." Catechism of Council of Trent - The Sacraments - The Eucharist

Summary

It is very clear from Scripture and Church teaching that the Real Presence was spoken of by our Lord and it is has always been a dogma of the Church. It is also clear that the Catholic Church has always taught that we must receive Holy Communion at least annually, must receive in the state of grace, and must also fast before receiving. Those who say otherwise cannot call themselves Catholic!

For further, physical proof of the real presence, see references to "Eucharistic miracles", which are first class miracles that have occurred through the Holy Eucharist in every century of the Catholic Church. Examples are on display for the public to see in churches all over the world. Perhaps one of the best references on the subject is the book, "Eucharistic miracles" by Joan Carroll Cruz. When looking at the phenomena and research done around these first class miracles, even non-Catholics cannot deny them!