ἐκεῖνον δεῖ αὐξάνειν, ἐμὲ δὲ ἐλαττοῦσθαι.

1. ἐκεῖνον
   that
2. δεῖ
   it is necessary
3. αὐξάνειν
   to increase
4.  
   ,
    
5. ἐμὲ
   me
6. δὲ
   but
   and
7. ἐλαττοῦσθαι
   to be diminished
   to be inferior
8.  
   .
    

He must increase, but I must decrease.