sir, the two ran into one another naturally enough at the corner; and then came the horrible part of the thing; for the man trampled calmly over the child’s body and left her screaming on the ground. (ch 1)

Enfield describes this as “hellish to see.”  He saw Mr. Hyde, grabbed him, and brought him back to the screaming child.  Enfield comments that everybody loathed to see the sight of the man, except for the doctor, who did not seem to care.

They arranged for him to pay 100 pounds to the family, and he went  into the door that Enfield pointed too and came back with a check.  He was curious about the strange house and the terrible man, and inquired as to his name.  He found out then that his name was Mr. Hyde.

When Mr. Utterson asks Enfield to describe this horrible looking man, he can’t be precise.

He is not easy to describe. There is something wrong with his appearance; something displeasing, something downright detestable. I never saw a man I so disliked, and yet I scarcely know why. (ch 1)

This first exposure to Mr. Hyde is mysterious, and foreshadows his later actions.  The incident with the check, so carefully described, hints at Mr. Hyde having a keeper—of course we do not find out until later that he is actually Dr. Jekyll.  Mr. Hyde does not care about the girl because he cares about no one and nothing.

In Robert Louis Stevenson's The Strange Case of Dr. Jekyll and Mr. Hyde, Mr. Richard Enfield only appears briefly, at the opening of the story. He is a distant kinsman of the main narrator, the lawyer, Mr. Utterson, with whom he enjoys a weekly walk every Sunday. On one of these walks, Enfield recounts a story of Mr. Hyde injuring a child and also identifies a house to which Hyde possesses a key.

Enfield is significant because he is an ordinary man, not a lawyer or doctor, and gives us a sense of how ordinary people react to Mr. Hyde. Enfield is not particularly imaginative or credulous, nor abnormally intelligent, but somewhat average, and thus almost stands in for us as readers. 

The episode that Enfield recounts serves two purposes in the plot. First, it gives us a sense of the sinister character of Mr. Hyde, and second it gives Mr. Utterson, a man not prone to idle curiosity, a motivation to investigate Dr. Jekyll's strange behavior.

Enfield's reaction to Hyde is particularly interesting:

... the man trampled calmly over the child's body and left her screaming on the ground. ... But there was one curious circumstance. I had taken a loathing to my gentleman at first sight. So had the child's family... [The doctor] was like the rest of us; ... sick and white with the desire to kill him.

This description sets up suspense only resolved when we discover that indeed Hyde is not just an ordinary bad person, but one scientifically engineered to be without moral nature.