The truck driver carries a special license, as the law 'requires' (him to do). = The truck driver carries a special license, 'as required by' law.
What will be 'required' of me if I accept the job? = What will I be 'required' to do if I accept the job?
The newspaper is 'required reading' [=reading that must be done] in my politics course.
(..) The clerk will read the report. The Committee on Privileges and Elections reports - - after hearing a number of witnesses, that justice to the Senate requires - - that Jefferson Smith no longer continue as a member of this body. They therefore recommend that the same do pass. (..)1939 Mr. Smith Goes to Washington