And from the circumstances he thinks that he is justifiably angered, and he speaks against the one who troubled him, saying, “If he had not come and spoken to me and annoyed me I should not have been sinned.”
This is a diabolic delusion! Could it really be that the one who spoke a word to him put that passion into him? He only showed that it already existed in him; so that he could, if he chose, repent of it.
But the man referred to above is like rotten bread, externally good, but inwardly all mouldy, and when someone crushes it, its corruption is revealed.
He was sitting at peace, as we were saying, but he had this anger inside him and he did not know it. One word to him from the other and the corruption hidden inside him showed itself.
If, therefore, he wants to receive mercy, then let him repent, purify himself, and spiritually progress; let him see that he should rather thank that brother, who had been an occasion of spiritual help to him.
Temptations would no longer vanquish him in the same way, but in proportion to his advance in this custom he would find that they became easier to bear.
For to the degree that a soul advances it becomes stronger and has the power to bear anything that comes upon it.
In the same way, if your beast of burden is strong you put a heavy load on it and he carries it; if he does happen to stumble, he gets up quickly and doesn’t seem to notice his fall.
But if he is a sickly animal the same load weighs him down. If he falls down it takes a lot of help to get him up.
So it is with the soul: if it goes on sinning it becomes sickly. Sin makes a man sickly and he has become weak and unsound because of it, for sin weakens and undermines the strength of those who give themselves over to it.
Therefore the slightest thing that happens to him will weigh him down; but if a man is advancing all the time in goodness, what happens to him becomes less and less difficult to bear in proportion to the ground he has gained.
And so this habit of accusing ourselves will work out well for us and bring us peace and much profit, especially since nothing can happen to us apart from the providence of God.
Dorotheos of Gaza (505-565 or 620): Conference 7 – How We Must Accuse Ourselves And Not Our Neighbours @ Pravoslavie.