The quote from Larry McMurtry's "Lonesome Dove" reflects on the inevitability of time passing and the importance of accepting that the past cannot be changed. It underscores a universal truth that yesterday's events are a part of history, moving away like a river's current, and once it is gone, it cannot be retrieved or altered. This poignant observation serves as a reminder to live in the present and acknowledge the transient nature of life.

In a broader context, the quote invites readers to ponder the significance of their actions and choices, as well as the impact of fleeting moments. It encourages embracing the present and looking forward, rather than dwelling on what has already passed. McMurtry's words resonate deeply with themes of nostalgia, loss, and the journey of life, making them especially poignant within the narrative of "Lonesome Dove."