Romans 8:28 (NA28) reads:
Οἴδαμεν δὲ ὅτι τοῖς ἀγαπῶσιν τὸν θεὸν πάντα συνεργεῖ εἰς ἀγαθόν, τοῖς κατὰ πρόθεσιν κλητοῖς οὖσιν.
There is also a textual variant that explicitly makes 'God' the subject of συνεργεῖ.
Here are some popular English translations of the verse:
We know that all things work together for good for those who love God, who are called according to his purpose (NRSV).
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 (NIV).
And we know that God causes all things to work together for good to those who love God, to those who are called according to His purpose (NASB).
Each of these three translations differs in a significant way, especially when using this verse to comfort grieving families. The NIV sits best with me on this verse, but is this the best reading of the Greek text?
πάντα ("all [things]") is neuter plural and can be either nominative or accusative, and could thus be either the subject or the direct object of συνεργεῖ, but if 'God' is the subject then πάντα can't be.
However, συνεργεῖ is usually intransitive, which means πάντα could be an adverbial accusative ("in all [things]"), which would coincide with the NIV reading.
Which reading is best given the Greek syntax of this passage and it's surrounding context?
Please consider internal and external evidence (i.e. the textual variants, other early translations or expositions by early commentators, etc.).