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

Perhaps we want to write like Shakespeare, maybe we want to be a writer like the great Old Testament prophet Isaiah. But the last thing we should be burdened with, Milton's suggesting here, is the fear of being late.

也许我们想向莎士比亚一样，也许想成为,伟大的旧约先知以赛亚,但弥尔顿说我们最不应该被，担心迟到所困。

耶鲁公开课 - 弥尔顿课程节选

In alluding to the prophet Isaiah in the prelude, Milton suggested that the iniquity of his lips had to be purged off -- burned off, with the live coal supplied by one of the seraphim.

弥尔顿在序曲中提到预言家艾赛亚，就是要表示他唇齿的邪恶,应该被净化，被其中一个，六翼天使用炭火烧掉。

耶鲁公开课 - 弥尔顿课程节选