15 From all which considerations it is clear that I have said nothing at all new concerning virginity and marriage, but have followed in all respects the judgment of older writers— of Ambrose, that is to say, and others who have discussed the doctrines of the Church. “And I would sooner follow them in their faults than copy the dull pedantry of the writers of today.” Let married men, if they please, swell with rage because I have said, “I ask you, what kind of good thing is that which forbids a man to pray, and which prevents him from receiving the body of Christ?” When I do my duty as a husband, I cannot fulfil the requirements of continence. The same apostle, in another place, commands us to pray always. “But if we are always to pray we must never yield to the claims of wedlock for, as often as I render her due to my wife, I incapacitate myself for prayer.” When I spoke thus it is clear that I relied on the words of the apostle: “Defraud ye not one the other, except it be with consent for a time, that you may give yourselves to... prayer.” The Apostle Paul tells us that when we have intercourse with our wives we cannot pray. If, then, sexual intercourse prevents what is less important— that is, prayer— how much more does it prevent what is more important— that is, the reception of the body of Christ? Peter, too, exhorts us to continence, that our “prayers be not hindered.” How, I should like to know, have I sinned in all this? What have I done? How have I been in fault? If the waters of a stream are thick and muddy, it is not the river-bed which is to blame, but the source. Am I attacked because I have ventured to add to the words of the apostle these words of my own: “What kind of good thing is that which prevents a man from receiving the body of Christ?” If so, I will make answer briefly thus: Which is the more important, to pray or to receive Christ's body? Surely to receive Christ's body. If, then, sexual intercourse hinders the less important thing, much more does it hinder that which is the more important.
I have said in the same treatise that David and they that were with him could not have lawfully eaten the show-bread had they not made answer that for three days they had not been defiled with women — not, of course, with harlots, intercourse with whom was forbidden by the law, but with their own wives, to whom they were lawfully united. Moreover, when the people were about to receive the law on Mount Sinai they were commanded to keep away from their wives for three days. I know that at Rome it is customary for the faithful always to receive the body of Christ, a custom which I neither censure nor endorse. “Let every man be fully persuaded in his own mind.” But I appeal to the consciences of those persons who after indulging in sexual intercourse on the same day receive the communion— having first, as Persius puts it, “washed off the night in a flowing stream,” and I ask such why they do not presume to approach the martyrs or to enter the churches. Is Christ of one mind abroad and of another at home? What is unlawful in church cannot be lawful at home. Nothing is hidden from God. “The night shines as the day” before Him. Let each man examine himself, and so let him approach the body of Christ. Not, of course, that the deferring of communion for one day or for two makes a Christian any the holier or that what I have not deserved today I shall deserve tomorrow or the day after. But if I grieve that I have not shared in Christ's body it does help me to avoid for a little while my wife's embraces, and to prefer to wedded love the love of Christ. A hard discipline, you will say, and one not to be borne. What man of the world could bear it? He that can bear it, I reply, let him bear it; he that cannot must look to himself. It is my business to say, not what each man can do or will do, but what the Scriptures inculcate.
Source: Letters (New Advent)