διὰ τοῦτο οὐκ ἠδύναντο πιστεύειν, ὅτι πάλιν εἶπεν Ἡσαΐας·

1. διὰ
   through
   because of
2. τοῦτο
   this
3. οὐκ
   not
4. ἠδύναντο
   they were able
   were able
5. πιστεύειν
   to believe
   to trust
6.  
   ,
    
7. ὅτι
   that
   because
8. πάλιν
   again
9. εἶπεν
   said
10. Ἡσαΐας
    Isaiah
11.  
    ·
     

Because of this they were not able to believe, because Isaiah said again,