Catholic teaching sees the Eucharist as Christ's transformative sacrifice on the cross and this Holy Communion must only be received worthily. This teaching is not partisan, but it certainly applies to political leaders who back abortion and euthanasia, Bishop Thomas Olmsted of Phoenix has said in an apostolic exhortation on the sacrament of the Holy Eucharist.
 
"Holy Communion is reserved for those, who with God's grace make a sincere effort to live this union with Christ and His Church by adhering to all that the Catholic Church believes and proclaims to be revealed by God," Bishop Olmsted said, explaining that Church teaching on this has "always been clear and based on Scripture."
 
This is why the Church "requires Catholic leaders who have publicly supported gravely immoral laws such as abortion and euthanasia to refrain from receiving Holy Communion until they publicly repent and receive the Sacrament of Penance," continued his exhortation, Veneremur Cernui.
 
"Not all moral issues have the same weight as abortion and euthanasia. The Church teaches that abortion or euthanasia is an intrinsically grave sin and that there is a grave and clear obligation for all Catholics to oppose them by conscientious objection," the bishop said.
 
Olmsted said that the current political climate means the Church can be "easily accused of favoring one party and singling out politicians of a certain party with such a teaching."
 
"However, the Church is only faithfully reaffirming its perennial teaching on the Eucharist and the worthy reception of Holy Communion which applies to every single person," said the bishop. Elsewhere in the letter, he explained that in an unworthy reception of Holy Communion, the sacrament "becomes a sacrilege."
 
He added: "the spiritual medicine becomes for that person – it is frightful to say – a form of spiritual poison."
 
"When we do not really believe in Jesus, when we do not really seek to conform our entire life to Him and receive Jesus even though we know that we have sinned against Him, then this just leads to a greater sin and betrayal," said Olmsted.
 
His exhortation included exhortations to an increase in devotional acts as well as to repentance and confession.
 
"The Church invites everyone to the Wedding Banquet while at the same time commits herself to helping everyone arrive properly dressed in a purified baptismal garment, lest the greatest Gift – the Eucharist – becomes his or her spiritual destruction," he said.
 
Olmsted published the exhortation April 1, Holy Thursday, which marks the institution of the Eucharist.
 
"The more the Lord in the Eucharist is our central focus, the more surely He will bring us through these dark and turbulent waters," said the bishop. "On this day when we commemorate the Institution of the Eucharist, I as your shepherd implore each of you to seek out Jesus in the Eucharist to be strengthened and renewed in your faith."
 
He voiced hope that everyone, whether strong in faith or weak, Catholic or not, will have a sincere "Eucharistic amazement" incited in them.
 
Olmsted  emphasized that Christ "meant what he said" in the Bread of Life discourse: "Very truly, I tell you, unless you eat the flesh of the Son of Man and drink his blood, you have no life in you. Those who eat my flesh and drink my blood have eternal life, and I will raise them up on the last day; for my flesh is true food and my blood is true drink."
 
"Despite the uproar caused by His teaching, Jesus did not soften His claim. On the contrary, He strengthened it," said the bishop. "The Eucharist is the supernatural food that keeps us going along the difficult journey towards the Promised Land of eternal salvation."
 
Invoking the imagery of the Old Testament, Olmsted portrayed the Mass as "the new Exodus from the Slavery of Sin." The Eucharist fulfills both the Jewish Passover and the Covenant of Israel.
 
"The first Passover saved the Israelites from death and led to their liberation from slavery," he said. "Every home that followed the rites commanded by God for this sacred meal were spared from the death of their firstborn sons."
 
"Just as the Hebrews had no alternative means of liberation other than the Passover lamb, there is no other means to salvation than through the grace of Jesus' own self-sacrifice," he continued, adding that the Mass is the "eternal memorial of Christ's sacrifice on the Cross."
 
"The sacrifice of Jesus on Calvary is perpetuated and made present to us in such a way that we can participate in it, linking our imperfect and sinful lives to the perfect and pure sacrifice of God and receiving all the divine benefits that flow from His eternal sacrifice," said Olmsted.
 
"When we attend Mass, do we seek to join Jesus in His total surrender to the Father's will? Do we bring our imperfections, our toil and sin, and lay them before Jesus to be consumed by His Death? We either say with Jesus, 'Into Your hands, Father, I commend my spirit, too!' or we choose to remain enslaved to our sin."
 
Olmsted compared present-day anxieties, uncertainties, and doubts to those which faced the Israelites as they sought the Promised Land.
 
"(T)he Church at large is experiencing a grave crisis of faith in the Eucharist," he said. "This crisis has inflicted additional significant implications for authentic Christian discipleship; namely, abysmal Mass attendance, declining vocations to marriage, priesthood, and religious life, waning Catholic influence in society. As a nation we are experiencing a torrent of assaults upon the truth."
 
"The Gospel message has been watered down or replaced with ambiguous worldly values," Olmsted continued. "Many Christians have abandoned Christ and His Gospel and turned to a secular culture for meaning that it cannot provide and to satiate a hunger that it can never satisfy."
 
"In such troubled waters, our greatest anchor in these storms is Christ Himself, found in the Holy Eucharist," said the bishop.
 
He chose the letter's title, translated as "down in adoration falling", from St. Thomas Aquinas' hymn Pange lingua gloriosi. He exhorted the faithful to adore Christ "with ever increasing reverence."
 
Every Mass, where Christ is present, is "immeasurable" in value and makes accessible "unfathomable" grace.
 
In response to a gift like the Eucharist, Olmsted asked various questions: "Do we really desire Him? Are we anxious to meet Him? Do we desire to encounter Him, become one with Him and receive the gifts He offers us through the Eucharist?"
 
Reception of Holy Communion is to change us and transform us into another Christ, he explained: "Being assimilated by Jesus in Holy Communion makes us like Him in our sentiments, desires, and our way of thinking. In Holy Communion, His heart nourishes our hearts; His pure, wise and loving desires purify our selfish ones, so that we not only know what He wants, but also start wanting the same more and more."
 
The Eucharist also transforms those who receive it well into "one body, one spirit in Christ."
 
Receiving Holy Communion "out of routine only, without openness to the Lord," means we do not receive all the graces God wants to give us. Olmsted said it can be easy for us to "lose our sense of wonder" at the miracle of the Eucharist. Faith, however, is the "first essential requirement" to receive all the benefits and effects of Holy Communion.
 
"If we receive the Lord with the right dispositions, God's grace will strengthen our resolve to follow, love and imitate Him. Our Lord Jesus deeply desires our union with Him in Holy Communion and through it He wishes to bring about our transformation into Him and the transformation of our society in which we live. But we, on our part, must ardently desire this union with Jesus Christ as well," he said.
 
He emphasized the importance of church decoration, art, music, vestments, incense, candles and other details as a way of expressing Christian devotion and faith. Eucharistic prayer and adoration are also important, as is respectful dress.
 
There is an "intrinsic connection" between the Sacrament of Penance and the Eucharist. Benedict XVI's 2007 apostolic exhortation Sacramentum caritatis warned against "a superficial approach that overlooks the need to be in a state of grace in order to approach sacramental communion worthily."  St. John Paul II's 2003 encyclical Ecclesia de Eucharistia said the Eucharist "presupposes that communion already exists, a communion that it seeks to consolidate and bring to perfection." Anyone conscious of grave sin must refrain from Holy Communion, said Olmsted's letter, citing the Catechism of the Catholic Church.

"There are situations when we can honor God more by abstaining from Holy Communion than by satisfying a personal desire to sacramentally receive Him in communion," he said, recounting a Catholic mother who abstained from Holy Communion for several years because she lived in an irregular marriage. Nonetheless, she faithfully attended Mass with her children and regularly took part in Eucharistic Adoration.
 
Olmsted emphasized the need to preserve Sunday as the "Day of the Lord" and the ultimate purpose of the week. Embracing some other thing, even a good thing, as more important than the worship of God will result in "bondage to some good but creaturely fixation" and "spiritual exhaustion and discouragement." Sunday is not simply about freedom from work, since freedom from servile work makes it so that "we are free to participate in the work of our Redemption."
 
He encouraged practical measures to make Sunday special, like turning off one's phone for extended periods, moving any commitments to work, family, or friends to other times, and finding ways "to make the experience of Sunday Mass truly joyful and festive." He suggested wearing one's best clothes, having a good meal with loved ones afterward, playing great music at home, phoning loved ones, spending time in Bible reading, performing acts of charity, or savoring "something truly beautiful in nature or art."
 
Daily Mass, a full hour of Eucharistic Adoration, or even a short visit to the tabernacle are also excellent ways to increase one's devotion. He encouraged priests to make the Eucharist the source of their priesthood's good work. Pastors should hold a Eucharistic procession each year in their parish. Eucharistic adoration is an evangelical opportunity.
 
"Many Catholics have wandered away from the practice of Sunday Mass, focusing more on work, sports, sleep, or entertainment rather than the Lord. There are also those who are physically there but not with their faith," said Olmsted. "They may come to Mass but do not receive Jesus with faith, love, and reverence because they think that they are only receiving a symbol rather than God Himself who died for them. There are those who physically come to Mass, but their hearts cannot wait to leave Jesus' presence. Indeed, the Eucharist is hard to believe! Thus, it is important for us to have patience and compassion for those whose faith is weak. Nevertheless, the call to faith is urgent."