The Enchiridion, Section 16 — In Plain English

Epictetus — The Slave

When you see someone crying because their child moved away or they lost money, don't get swept up in their pain. Stay clear-headed. Be ready to remind yourself: "What's hurting this person isn't what happened to them — someone else might not be bothered by the same thing — it's how they're choosing to see it." When you talk to them, though, don't act superior. Meet them where they are. Groan with them if you need to. Just make sure you don't start believing their groans on the inside.

Epictetus — The Slave Original

When you see anyone weeping for grief, either that his son has gone abroad or that he has suffered in his affairs, take care not to be overcome by the apparent evil, but discriminate and be ready to say, “What hurts this man is not this occurrence itself—for another man might not be hurt by it—but the view he chooses to take of it.” As far as conversation goes, however, do not disdain to accommodate yourself to him and, if need be, to groan with him. Take heed, however, not to groan inwardly, too.