My family and I have spent several enjoyable vacations on the Atlantic Ocean, both at Cape Cod and along the rockbound coast of Maine. Always we have enjoyed the beaches and the pastimes attendant to them. One perennial pastime is the building of sand castles, and I well remember our children building them close to the sea’s edge and how, with tidal changes, the parameters of the ebbing and flowing would be altered, often allowing the ocean to become increasingly bold in assailing what the children had so carefully created.

There are corresponding patterns in human life. It could be said that in sleeping we ebb and upon rising, flow. Or in conversation between two persons, one becomes quiet (ebbs) so that the other can talk (flow). This celebrated sixth chapter of Isaiah is likewise about …