Full Idea
The pains of the soul are worst, for the flesh is only sensible of present affliction, but the soul feels the past, present and future.
Gist of Idea
Pains of the soul are worse than pains of the body, because it feels the past and future
Source
report of Epicurus (fragments/reports [c.289 BCE]) by Diogenes Laertius - Lives of Eminent Philosophers 10.29
Book Reference
Diogenes Laertius: 'Diogenes Laertius', ed/tr. Yonge,C.D. [Henry G. Bohn 1853], p.473
A Reaction
I don't think feeling extended across time is very relevant. What matters is that pains of the soul usually endure far longer than physical suffering.