Originally, Lear wishes to free himself of the burdens of ruling his kingdom because he is aware of his old age and wishes to "crawl unburdened toward death" (1.1.42). As his choice of the verb "crawl" suggests, Lear has a sense that old age forces the individual to remember his or her animal aspect—that is, the fact that human beings, like animals, are subjected to the forces of physical nature and have physical needs.
Age as Goneril and Regan unkindly observe at various points, brings a kind of weakness with it. Regan mocks Lear: "O, sir, you are old […] You should be ruled and led/ By some discretion that discerns your state/ Better than you yourself" [2.4.165-9]. Yet, together with the father-child bond, the play also suggests at various points that age should command respect. The fact that Lear's daughters abuse him for being old makes their cruelty seem all the worse and also indicates that all they care about is power, without any thought for wisdom. Cornwall and Regan's brutality to Gloucester is similarly heightened by our awareness of his age—for instance, when Regan plucks Gloucester's white beard in 3.7.
Old Age ThemeTracker
Old Age Quotes in King Lear
Nature I you stands on the very verge
Of his confine."
Lear: Let me wipe it first; it smells of mortality."
We two alone will sing like birds in the cage."