Here's a notable passage by Khalil Gibran concerning the theme of growing old, from his poem "Youth and Age":

"In my youth the heart of dawn was in my heart, and the songs of April were in my ears. But my soul was sad unto death, and I knew not why. Now, however, I know that sadness is but the tide between two seas of joy, and I welcome it, and I seat myself upon its shores and watch the ships that sail from the one into the other. In my youth I longed for the unknown, and for the unknown I am still longing. But in the days of my youth longing embraced necessity that knows naught of patience. Today I long not less, but my longing is friendly with patience, and even waiting. And I know that all this desire that moves within me is one of those laws that turns universes around one another in quiet ecstasy, in swift passion which your eyes deem stillness, and your mind a mystery."

This passage illustrates Gibran's view on aging as a process where one learns patience and acceptance, reflecting on how perspectives and emotions evolve with age.

I really like that quote