As humans we must change ourselves in everyday, months & years we live through. A living thing always evolves & changes over time. If we don't change, it means we are dead objects, not animated beings.
The Ethiopian cannot change his skin nor the leopard his spots.
(Henry David Thoreau (1817-1862), U.S. philosopher, author, naturalist. Letter, November 14, 1847, to Ralph Waldo Emerson, in The Writings of Henry David Thoreau, vol. 6, p. 140, Houghton Mifflin (1906).)
(William Shakespeare (1564-1616), British poet. No, Time, thou shalt not boast that I do change (l. 1). . .
The Unabridged William Shakespeare, William George Clark and William Aldis Wright, eds. (1989) Running Press.)