(this is a little dated but…) Brandon Watson has a post on doing the statement of purpose for the PhD application process – explaining why you want to do PhD work and how your schooling up this point has prepared you for this daunting but exciting task. He has good advice.
I just got worried when I read it mainly because, well, I did NOTHING to prepare myself specifically for PhD work, I just worked on an MDiv in a general sense (which isn’t bad in and of itself) – so if I were to apply, I’d be in a tough spot.
But if you are thinking the Lord is calling you to that level of study and work, then you will probably want to take what Brandon has to say to heart. Start now to plan forPhD work – shape your courses in specific ways that will better prepare you for that level of work (especially getting the languages down). I’m pretty certain doing a PhD is hard work but work well worth doing when the Lord calls you to it. So start out well so you can finish out well.