{For this cause they could not believe} (dia touto ouk
edunanto pisteuein). Touto (this) seems to have a double
reference (to what precedes and to what follows) as in  8:47 .
The negative imperfect (double augment, edunanto) of dunamai.
John is not absolving these Jews from moral responsibility, but
only showing that the words of Isaiah "had to be fulfilled, for
they were the expression of Divine foreknowledge " (Bernard).