“Cato left this world in such a manner as if he were delighted that he had found an opportunity of dying; for that God who presides in us forbids our departure hence without his leave.
But when God himself has given us a just cause, as formerly he did to Socrates, and lately to Cato, and often to many others — in such a case, certainly every man of sense would gladly exchange this darkness for that light.
For the whole life of a philosopher is, as the same philosopher says, a meditation on death.” (Tusculan Disputations, 1.30)
Cicero on good reasons for dying