Dative Confusion

With Part III of Unit 12, No. 10, I am supposed to write,
“It is not easy for them to obey a harsh law.”

The answer book wrote,
“οὐ ῥᾴδιον or (οὐ ῥᾴδιόν ἐστιν) αυτοῖς χαλεπῷ νόμῳ πείθσθαι.”

I am not sure what rules are placing αυτοῖς χαλεπῷ νόμῳ in the dative. Is αυτοῖς in the dative because it is a dative of reference or a dative of advantage/disadvantage? Are χαλεπῷ νόμῳ in the dative because of the verb?

Are there other rules applying to the dative?

In unit 11 you will find :

  1. Idiomatic Meanings of the Middle Voice. It takes time for the student to get an adequate sense of the range of implications conveyed by the middle voice. Here are some examples of common verbs to illustrate shifts in meaning noticeable between active and middle. πείθω + acc. I persuade, urge πείθομαι + dat. I obey, trust, believe (a person)

Sometimes you can find the answers to your questions in the index and the text.

I did read that in chapter 11, but with three datives in a row, I am trying to make sure which rules are applying to which words.

I am sorry I did not read your post carefully enough.

I think this is the exemplar you need (p80)

  1. Dative of Reference. The person to whom a statement is limited or in whose opin-ion a statement is true is expressed in the dative case. Such a dative of reference is often used in sentences with an infinitive phrase as subject.

τῷ σοφῷ ὁ βίος οὐ χαλεπός. For a wise man life is not difficult.