The dynamic of friendship is almost always underestimated as a constant force in human life: a diminishing circle of friends is the first terrible diagnostic of a life in deep trouble: of overwork, of too much emphasis on a professional identity, of forgetting who will be there when our armored personalities run into the inevitable natural disasters and vulnerabilities found in even the most average existence.
The ultimate touchstone of friendship is not improvement, neither of the other nor of the self, the ultimate touchstone is witness ... to have walked with them and to have believed in them, and sometimes just to have accompanied them for however brief a span, on a journey impossible to accomplish alone."
Source: Consolations: The Solace, Nourishment and Underlying Meaning of Everyday Words - David Whyte