Meditations, Book III, Section 15

Meditations, Book III, Section 15:

Be not deceived; for thou shalt never live to read thy moral commentaries, nor the acts of the famous Romans and Grecians; nor those excerpta from several books; all which thou hadst provided and laid up for thyself against thine old age. Hasten therefore to an end, and giving over all vain hopes, help thyself in time if thou carest for thyself, as thou oughtest to do.

Another translation:

No longer wander at hazard; for neither wilt thou read thy own memoirs, nor the acts of the ancient Romans and Hellenes, and the selections from books which thou wast reserving for thy old age. Hasten then to the end which thou hast before thee, and throwing away idle hopes, come to thy own aid, if thou carest at all for thyself, while it is in thy power.