“When the sins of others come to mind, the soul that wishes to be in repose shall flee from that as from the pain of hell, searching in God for remedy for help against it, for the beholding of others’ sins makes, as it were, a thick mist before the eye of the soul, and we cannot for the time see the fairness of God (unless we can behold another's sins with contrition with him, with compassion on him and with holy desire to God for him) for without this it troubles and tempts and hinders the soul that beholds those sins" (Chapter 76).
Through a rather complicated sentence, Julian nonetheless describes a quite simple and familiar situation — not only about how we “see” people, but also how we “talk” to them, or about them.
In daily life, we unfailingly notice each other’s “quirks” — it is rare to have one’s mind and heart so fixed on God that one fails to register the apparent wrongs, miniscule or grand, that we notice others commit and leave behind. Even allowing the mind to stray into noticing such particularities without contrition and compassion is to step into the thick mist Julian warns about.
Instead of blundering into the mist, such occasions can end differently: they can be invitations to realize in one's heart that one's own faults and quirks, even if unnoticed for the time, are still there, still borne with by others patiently (or not), and "what am I doing about all that!" Even if we should be well on our way to sainthood, there is going to be a mixture of well and woe in us, and we always have the choice of which to give our attention to both in ourselves and others. Trusting in God's love for us, not our own supposed goodness, is the way out of the muddle.