As you may have guessed, because you have this on your handout, Milton is alluding here to the famous words of the Old Testament prophet Isaiah.

你们可能已经猜到了，因为讲义上都有，弥尔顿在这儿影射到这些,先知艾赛亚旧约里的一些很有名的词。

耶鲁公开课 - 弥尔顿课程节选