What is the author's purpose

An author's purpose may be to persuade you, entertain you, or give information to the reader about a particular type of thing.

lets none because you provide no details.

the answer would be: it explains that at least one son must join the church

the expression ''as the tithe of his sons'' indicates how his father intended for at least one of his sons to serve the church. this phrase demonstrates that his father offered him as a last resort since none of his brothers chose to serve the church.

hope this answer you: )!