Final answer:
In the given statement, 'he' refers to the person sending the message.
Step-by-step explanation:
The pronoun 'he' in the given statement refers to the person sending the message. In the line, 'He hath not failed to pester us with message / Importing the surrender of those lands / Lost by his father', the speaker is talking about a person who has been consistently bothering them with messages about their father's lost lands. So, option 4) The person sending the message is the correct answer.