The Catholic Prayer Book and Manual of Meditations/Preparation for Communion
PREPARATION FOR COMMUNION.
To go to the table of our Lord, it is necessary: 1st, To be in a state of grace. Woe to him who would venture to approach the most holy table of the Lord with a conscience stained with mortal sin. Such a bad Christian would be guilty, like the traitor Judas, of sacrilege; for of such an unfortunate one it is written: “And after the morsel (the Holy Communion), Satan entered into him.”
Therefore St. Paul, in words of earnest warning, says to us : “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 Cor. xi. 28.)
By this is meant that he who receives communion unworthily, commits the greatest outrage against the body and blood of Jesus Christ, and, like the Jews who killed Jesus Christ, becomes also guilty of his murder.
2. One must live with his neighbours in peace and Christian unity. Communion means union, and is so called because it is the image of the perfect union and brotherly love of all the faithful in Christ. Jesus Christ teaches us that we must not bring our sacrifices to the altar, if we remember that our neighbour has anything against us; with how much greater reason are we bound not to approach the table of the Lord, if we ourselves cherish in our heart a hatred against our neighbour! We must first be reconciled with our enemy.
3. On the evening before communion, you ought to prepare for it by devout prayer, and by reading some pious book, and withdraw, in reverence for the Holy Sacrament, from all noisy and distracting amusements.
4. The body of Christ must be received fasting, that is, We must neither eat nor drink anything after midnight. But those who are dangerously sick, and receive this most holy Sacrament as a viaticum, are dispensed from this.
5. Every one should approach the table of the Lord with devotion, decently and modestly dressed, and without any vain ornaments or display of fashion.