John 3:15

ἵνα πᾶς ὁ πιστεύων ἐν αὐτῷ ἔχῃ ζωὴν αἰώνιον

So that all those believing in him might have eternal life.


 * ἵνα calls for a subjunctive and it is ἔχῃ - might have
 * πιστεύων ἐν αὐτῷ - notice the presence of the preposition ἐν which takes a dative αὐτῷ. Contrast with the next verse John 3:16
 * ζωὴν αἰώνιον - doesn't look feminine? Mounce classes this adjective as a 2-2 adjective, meaning that the feminine follows the 2nd declension inflection also.