Ante-Nicene Fathers, Vol IX:
Origen's Commentary on the Gospel of Matthew.: Chapter XV

15.  Eating with Unwashed Heart Defiles the Man.

Next to this let us see how the things which proceed out and defile the man do not defile the man because of their proceeding out of the mouth, but have the cause of their defilement in the heart, when there come forth out of it, before those things which proceed through the mouth, evil thoughts, of which the species are—murders, adulteries, fornications, thefts, false witness, railings. 5479   For these are the things which defile the man, when they come forth out of the heart, and going out from it proceed through the mouth; so that, if they did not come out of the heart, but were retained there somewhere about the heart, and were not allowed to be spoken through the mouth, p. 444 they would very quickly disappear, and a man would be no more defiled.  The spring and source, then, of every sin are evil thoughts; for, unless these gained the mastery, neither murders nor adulteries nor any other such thing would exist.  Therefore, each man must keep his own heart with all watchfulness; 5480 for when the Lord comes in the day of judgment, “He will bring to light the hidden things of darkness and will make manifest the counsels of the hearts,” 5481 “all the thoughts of men meanwhile accusing or else excusing them,” 5482 “when their own devices have beset them about.” 5483   But of such a nature are the evil thoughts that sometimes they make worthy of censure even those things which seem good, and which, so far as the judgment of the masses is concerned, are worthy of praise.  Accordingly, if we do alms before men, having in our thoughts the design of appearing to men philanthropic, and of being honoured because of philanthropy, we receive the reward from men; 5484 and, universally, everything that is done with the consciousness in the doer that he will be glorified by men, has no reward from Him who beholds in secret, and renders the reward to those who are pure, in secret.  So, too, therefore, is it with apparent purity if it is influenced by considerations of vain glory or love of gain; and the teaching which is thought to be the teaching of the Church, if it becomes servile through the word of flattery, either when it is made the excuse for covetousness, or when any one seeks glory from men because of his teaching, is not reckoned to be the teaching of those “who have been set by God in the Church:  first, apostles; secondly, prophets; and thirdly, teachers.” 5485   And you will say the like in the case of him who seeks the office of a bishop for the sake of glory with men, or of flattery from men, or for the sake of the gain received from those who, coming over to the word, give in the name of piety; for a bishop of this kind at any rate does not “desire a good work,” 5486 nor can he be without reproach, nor temperate, nor sober-minded, as he is intoxicated with glory and intemperately satiated with it.  And the same also you will say about the elders and deacons.  And if we seem to some to have made a digression in speaking of these things, consider if it were not necessary that they should be said, because that evil thoughts are the spring of all sins, and can pollute even those actions which, if they were done apart from evil thoughts, would have justified the man who did them.  We have thus investigated according to our ability what are the things which defile; but to eat with unwashed hands does not defile the man; but if we must say it with boldness, with unwashed heart to eat anything whatsoever which is the natural food of our reason, defileth the man.

Footnotes

Matt. 15:18, 19.

Prov. iv. 23.

1 Cor. iv. 5.

Rom. ii. 15.

Hos. vii. 2.

Matt. 6:1, 2.

1 Cor. xii. 28.

1 Tim. iii. 1.