Temporariness is an essential ingredient of our human incompleteness. Many relationships, by their very nature, are temporary. Sometimes we are caught in a mindset that says a relationship must be permanent in order to have meaning. We must grieve and give up the people we have lost to distance and difference if we are to make friends with the strangers who are moving into the circle of the present. We will not be able to speak of a friend who was once a stranger, unless we can speak of the stranger who was once a friend.
Friends do become strangers in our world of the temporary, just as strangers become friends.
To be sure, there are some people who can claim a life long friend. The only people I know who have a genuine permanent arrangement with life are those whose lives have ended. In all the rest of us change is still going on. As a matter of fact, change is a basic characteristic of life, and without it, life as we know it would be snuffed out. The Psalmist reminds us that permanence belongs only to God.