I was thinking about someone I know whose life (difficulties, gifts, circumstances, etc.) is constituted by such fathomless and intricate mystery that I scarcely know how to pray for her. To attempt to pray for her is to touch the outskirts of a mystery which is so much greater than the "outcomes" I would like to see--health, well-being, etc.--though I can't not pray for those too.
Then it occurred to me--we're all like that. We're all in some sense uncharted territory for each other, and for ourselves as well.
That took me back to Romans 8 (again):
"In the same way, the Spirit helps us in our weakness. We do not know what we ought to pray for, but the Spirit himself intercedes for us with groans that words cannot express. And he who searches our hearts knows the mind of the Spirit, because the Spirit intercedes for the saints in accordance with God's will. And we know that in all things God works for the good of those who love him, who have been called according to his purpose. For those God foreknew he also predestined to be conformed to the likeness of his Son, that he might be the firstborn among many brothers. And those he predestined, he also called; those he called, he also justified; those he justified, he also glorified."