What deuterocanonical books are quoted in the New Testament? When talking with a Catholic friend (I'm a Protestant) about the apocrypha/deuterocanonical books, it occurred to me that a possible argument for their inclusion in the Canon would be their authority, measured in two ways:


Claiming to be speaking on behalf of God (e.g "Thus saith the Lord...")
Being quoted by other books considered to be a part of the Canon


Thus, I was wondering which (if any) books are quoted or referenced in the New Testament?

Also, are there any OT books that quote the apocrypha? (I have a feeling this may be a stupid question since, if I understand correctly, they were mostly written before the apocrypha.)
There are no direct quotes, at least, not in the sense that, for example, Isaiah is quoted, but there are certainly several allusions and parallel passages. Here is a list of some of them from both NT and OT (and yes, I am well aware that some of those are debatable).

As to "other books quoting them," it should be noted that neither Song of Songs, Esther, or Ecclesiastes are quoted elsewhere in scripture. It should also be noted that the Apocalypse of Enoch is quoted in Jude as well as I &amp; II Peter (and it is fairly obviously quoted in Jude and II Peter) and no one sees that document as canonical.