Canon 10
Whence it is not right either that those of the clergy who have deserted of their own accord, and have lapsed, and taken up the contest afresh, should remain any longer in their sacred office, inasmuch as they have left destitute the flock of the Lord, and brought blame upon themselves, which thing did not one of the apostles. For when the blessed apostle Paul had undergone many persecutions, and had shown forth the prizes of many contests, though he knew that it was far better to “depart, and to be with Christ,” yet he brings this forward, and says, “Nevertheless to abide in the flesh is more needful for you.” For considering not his own advantage but the advantage of many, that they might be saved, he judged it more necessary than his own rest to remain with the brethren, and to have a care for them; who also would have him that teaches to be “in doctrine” an example to the faithful. Whence it follows that those who, contending in prison, have fallen from their ministry, and have again taken up the struggle, are plainly wanting in perception. For how else is it that they seek for that which they have left, when in this present time they can be useful to the brethren? For as long as they remained firm and stable, of that which they had done contrary to reason, of this indulgence was accorded them. But when they lapsed, as having carried themselves with ostentation, and brought reproach upon themselves, they can no longer discharge their sacred ministry; and, therefore, let them the rather take heed to pass their life in humility, ceasing from vainglory. For communion is sufficient for them, which is granted them with diligence and care for two causes; both that they should not seem to be afflicted with sorrow, and hence by violence seize on their departure from this world; and also lest any of the lapsed should have a pretext for being remiss by occasion of the punishment. And these indeed will reap more shame and ignominy than all others, even as he who laid the foundation and was not able to finish it; for “all that pass by,” He says, will begin to mock him, saying, “This man laid the foundation, and was not able to finish it.”
Balsamon. The father having spoken of those who of their own accord went over to the contest of martyrdom, now also speaks of those of the clergy who are in such a case, and he says, that if any clergyman has of his own accord sought the contest, and then, not being able to bear the tortures, has fallen, but returning to himself, has recanted his error, and before the tyrants confessed himself a Christian, such a one shall no longer discharge his sacred ministry, because he has deserted the Lord's flock, and because, having of his own accord sought the contest, through not being able to endure the torment, he has brought reproach upon himself. For to neglect the teaching of the people, and to prefer their own advantage, this did not the apostles. For the mighty Paul, after that he had endured many torments, though he perceived that it was far better to leave this life, yet chose rather to live and to be tormented for the salvation and instruction of the people. They are therefore altogether devoid of perception who seek the sacred ministry from which they have fallen of their own accord. For how is it that they seek for that which they have left, when they are able in this season of persecution, that is, to be useful to their brethren? If indeed they had not fallen, of that which they had done contrary to reason, their spontaneous flight for instance, or their slackness in teaching and confirming the brethren, of these things indulgence would be extended to them. But if from their own arrogance and conceit they have lapsed—for of such a nature is it rashly to venture to expose themselves to torture, and not to be able to endure it, and thus a triumph has been gained over them—they cannot any longer execute their sacred office. Wherefore let them the rather take heed that they perfect their confession by humility, ceasing from the vainglory of seeking for the sacred ministry; for communion with the faithful is sufficient for them, which is granted for two reasons, with diligent caution, and just judgment. For if we say that we will not hold them to be communicants, we shall both afflict them with grief, giving our sentence as it were that they should depart this life with violence; and we shall cause others also, who may have lapsed, and wish to return to what is right, to be negligent and remiss in this respect, having as a pretext, that they will not be admitted to communicate with the faithful, even though after their fall they should confess the faith, who, if they are not converted, will undergo more shame and ignominy than others, even as he who laid the foundation, and did not finish the building. For such a one do those resemble, who, for Christ's sake indeed, have offered themselves to be tormented, and having laid as it were a good foundation, have not been able to perfect that which is good by reason of their fall. Observe, then, that not even confession for Christ's sake restores him who has once lapsed and thus become an alien from his clerical office.
Source: The Canonical Epistle (New Advent)