Whom does dryden describe as "the man who of all mordern, and perhaps anicent poets. had the largest and most comprehensive soul?

In paragraph 5, president obama remarks: “you know, when trayvon martin was first shot i said that this could have been my son. another way of saying that is trayvon martin could have been me 35 years ago.” how does president obama use rhetoric in this quote to contribute to the overall meaning of his speech?