What is a relative clause ?

A relative clause is a clause that modifies a noun.  A relative clause is often called an adjective clause because it functions as an adjective in a sentence.

A relative clause is introduced by a relative pronoun, a relative adverb, or a zero relative.

Relative pronouns are which, that, who, whom, whose.

e.g.  She is the person to whom I have sent the letter.

Relative adverbs are where, when, why.

e.g.  I will always remember the day when I met her.

A zero relative is occuring when we omit the relative pronoun.

e.g.  The man you hired  is not very responsible. (the relative pronoun is left out because it is the object of the relative clause)

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.

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