[171] But this is not so much a positive exhortation as an announcement of his opinion, for if he had been giving a positive recommendation he would have said, "Do not sow, and do not reap:" but as he is only giving his opinion, he says, "Ye shall not sow, neither shall ye reap." For as to those things with which we meet by the voluntary bounty of nature, of these we cannot find either the beginnings or the ends in ourselves as if we were the causes of them: therefore the beginning is the seed-time and the end the harvest time.