Found at Aspiring Community:
 
The Bridge Builder


                        An old man, going a lone highway,
                        Came, at the evening, cold and gray,
                        To a chasm, vast, and deep, and wide,
                        Through which was flowing a sullen tide.
                        The old man crossed in the twilight dim;
                        The sullen stream had no fears for him;
                        But he turned, when safe on the other side,
                        And built a bridge to span the tide.
                        "Old man," said a fellow pilgrim, near,
                        "You are wasting strength with building here;
                        Your journey will end with the ending day;
                        You never again must pass this way;
                        You have crossed the chasm, deep and wide-
                        Why build you a bridge at the eventide?"
                        The builder lifted his old gray head:
                        "Good friend, in the path I have come," he said,
                        "There followeth after me today,
                        A youth, whose feet must pass this way.
                        This chasm, that has been naught to me,
                        To that fair-haired youth may a pitfall be.
                        He, too, must cross in the twilight dim;
                        Good friend, I am building the bridge for him."

                        Will Allen Dromgoole