The answer telling how a solitary can discover his faults.
John: To those who are really seeking relief, healing remedies from the true Physician of souls will certainly not be wanting; and to those above all will they be given who do not disregard their ill-condition (either because they despair of it, or because they do not care about it), nor hide the danger they are in from their wound, nor in their wanton heart reject the remedy of penitence, but with an humble and yet careful heart flee to the heavenly Physician for the diseases they have contracted from ignorance or error or necessity. And so we ought to know that if we retire to solitude or secret places, without our faults being first cured, their operation is but repressed, while the power of feeling them is not extinguished. For the root of all sins not having been eradicated is still lying hid in us, or rather creeping up, and that it is still alive we can tell by these signs. For instance, if, when we are living in solitude we receive the approach of some brethren, or any very slight tarrying on their part, with any anxiety or fretfulness of mind, we should recognize that an incentive to the most hasty impatience is still existing in us. But if when we are hoping for the coming of a brother, and from some cause he perhaps delays a little, our mental indignation either silently blames his slowness, and annoyance at this inconvenient waiting disturbs our mind, the examination of our conscience will show that the sin of anger and vexation is plainly still remaining in us. Again, if when a brother asks for our book to read, or for some other article to use, his request annoys us, or a refusal on our part disgusts him, there can be no doubt that we are still entangled in the meshes of avarice or covetousness. But if a sudden thought or a passage of Holy Scripture brings up the recollection of a woman and we feel that we are at all attracted towards her, we should know that the fire of fornication is not yet extinguished in us. But if on a comparison of our own strictness with the laxity of another even the slightest conceit tries our mind, it is clear that we are affected with the dreadful plague of pride. When then we detect these signs of faults in our heart, we should clearly recognize that it is only the opportunity and not the passion of sin of which we are deprived. And certainly these passions, if at any time we were to mingle in the ordinary life of men, would at once start up from their lurking places in our thoughts and prove that they did not then for the first time come into existence when they broke out, but that they were then at last made public, because they had been long lying hid. And so even a solitary can detect by sure signs that the roots of each fault are still implanted in him, if he tries not to show his purity to men, but to maintain it inviolate in His sight, from whom no secrets of the heart can be hid.