The poet is talking about a little boy who has lost his ball while playing with his ball. The ball skipped from his hand and went into the close by water body.
The poet is describing this sight of the boy losing his favourite ball made him think about the boy and his reaction in such a situation. The boy was vulnerably looking into the water body where his ball had gone.
He was gloomy and was shaking with fear. He got so engrossed in sorrow that he kept standing near the harbour for a very long time and kept on looking for his ball. The poet wanted to comfort him by saying that he will get new balls or would give him some money to buy another ball.
But he stopped himself from doing so because he thought that money may bring a new ball but will not bring the reminiscences and feelings attached to the lost ball. He further says that the time has come for the boy to learn his errands.
The poet wants to say that now the boy will learn the toughest lesson of life, of accepting the cruel realities of life that one day we might lose our loved ones and our loved things.