Here are the theology and biblical studies journals I practiced translating when preparing for my Spanish reading exam for the Duke Th.D. (Doctor of Theology) program.
They are available through ATLA. (ATLA link for Duke students). Many people have free online access to these journals through ATLA or EbscoHost or Academic Search Premier through their public library. Just go to the "Research" or "Magazines" or "Journals" page of your local county or city library. You will probably have to put in your library card number. Or call the library and get help from a librarian.
I have also read some homilies from the martyred Oscar Romero, liberation theology from Gustavo Gutiérrez, and some theology by evangelicals Samuel Escobar and René Padilla.
I practiced with English and Spanish versions of books:
See my comments and advice about theological language reading exams at my website www.theologicalgerman.com. My advice is about German but much of it would be applicable to learning Spanish. See especially Tips for German Reading Exams. See also the Duke Th.D. program language exam requirements as a sample of what Ph.D. theological exams are like.