John vi. 57, R.V.  The Greek is ἐγὼ ζῶ διὰ τὸν πατέρα, i.e. not through or by the Father, but “because of” or “on account of” the Father.  “The preposition (Vulg. propter Patrem) describes the ground or object, not the instrument or agent (by, through διὰ τοῦ π.).  Complete devotion to the Father is the essence of the life of the Son; and so complete devotion to the Son is the life of the believer.  It seems better to give this full sense to the word than to take it as equivalent to ‘by reason of;’ that is, ‘I live because the Father lives.’”  Westcott, St. John ad loc.