Seneca uses mastery here as ownership of one’s time and direction rather than power over other people.
On the Shortness of Life, Chapter II; follows the example of people living through chains of obligation.
“No one asserts his claim to himself.”
A person can defend property yet fail to protect attention, allowing other demands to occupy the life that only they can decide how to use.
On the Shortness of Life, Chapter II; part of Seneca’s criticism of people who give all their time away.
“Begin at once to live, and count each separate day as a separate life.”
Seneca argues against postponing life into an imagined future and asks the reader to treat the present day as complete enough for deliberate living.
Moral Letters to Lucilius, Letter 101.
“No man can have a peaceful life who thinks too much about lengthening it.”
An obsession with extending life can undermine the peace of the life already present, because fear of ending displaces attention from living.
Moral Letters to Lucilius, Letter 4.
“You squander time as if you drew from a full and abundant supply.”
Time is treated as a finite resource that becomes easy to waste when its remaining amount is assumed rather than known.
On the Shortness of Life, Chapter III; part of Seneca’s warning against acting as though every day were guaranteed.
“Be cheerful also, and seek not external help nor the tranquillity which others give.”
Marcus places steadiness inside the governing mind rather than in reassurance supplied by other people, emphasizing an internal source of composure while still writing within a larger Stoic ethic of social duty.
Meditations, Book III, section 5, George Long translation; Project Gutenberg #6920/#15877. The sentence immediately precedes “A man then must stand erect, not be kept erect by others,” making the inward-reliance context explicit.
“The mind is its own place.”
The statement emphasizes how mental framing can alter the experience of circumstances, for good or ill.
Paradise Lost (1667), Book I, line 254; retained legacy short extract from the fuller Satan sentence beginning ‘The mind is its own place’ and continuing into line 255. It is the same underlying passage as the longer catalog record, not a separate fifth passage.
