καὶ ὁ ἑωρακὼς μεμαρτύρηκε, καὶ ἀληθινὴ αὐτοῦ ἐστιν ἡ μαρτυρία, κἀκεῖνος οἶδεν ὅτι ἀληθῆ λέγει, ἵνα καὶ ὑμεῖς πιστεύσητε.

1. καὶ
   and
2. ὁ
   the
3. ἑωρακὼς
   having seen
4. μεμαρτύρηκε
   has testified
   has borne witness, he has testified
5.  
   ,
    
6. καὶ
   and
7. ἀληθινὴ
   true
8. αὐτοῦ
   his
9. ἐστιν
   is
10. ἡ
    the
    or
11. μαρτυρία
    testimonies
    testimony
12.  
    ,
     
13. κἀκεῖνος
    and that one
    and he
14. οἶδεν
    knows
15. ὅτι
    that
    because
16. ἀληθῆ
    true
17. λέγει
    says
18.  
    ,
     
19. ἵνα
    so that
20. καὶ
    and
21. ὑμεῖς
    you
22. πιστεύσητε
    you may believe
    you will believe, you believe
23.  
    .
     

And the one having seen has testified, and his testimony is true, and that one knows that he says true things, so that you also may believe.