John 4:14

ὃς δ' ἂν πίῃ ἐκ τοῦ ὕδατος οὗ ἐγὼ δώσω αὐτῷ, οὐ μὴ διψήσει εἰς τὸν αἰῶνα, ἀλλὰ τὸ ὕδωρ ὃ ἐγὼ δώσω αὐτῷ γενήσεται ἐν αὐτῷ πηγὴ ὕδατος ἁλλομένου εἰς ζωὴν αἰώνιον.

Rough Word-by-word:
who but would might drink from the water which I I will give to him, not not he will thirst into the age, but the water which I I will give to him it will become in to him a spring of water welling up into life eternal.

Smooth translation:
but whoever would drink from the water which I myself will give him, will not ever thirst forever, but the water which I will give him will become in him a spring of water welling up to eternal life.

ὃς relative pronoun nominative singular masculine "who" (correlative with ἂν)

δ' post positive conjunction "and/but"

ἂν particle of contingency "would" (correlative with ὃς)

πίῃ present active subjunctive 3rd singular from πίνω (I drink) "he might drink"

ἐκ genitive preposition "from/out of"

τοῦ definite article genitive singular neuter "the"

ὕδατος noun genitive singular neuter "water"

οὗ relative pronoun "which"

ἐγὼ personal pronoun nominative singular masculine "I"

δώσω verb future active indicative 1st singular from δίδωμι (I give) "I will give"

αὐτῷ pronoun dative singular masculine "to him"

οὐ adverb of negation "not" (correlative with μὴ denotes strong negation)

μὴ adverb of negation "not" (correlative with οὐ denotes strong negation)

διψήσει verb future active indicative 3rd singular from διψάω (I thirst) "he will thirst"

εἰς accusative preposition "in/into"

τὸν definite article accusative singular masculine "the"

αἰῶνα noun accusative singular masculine "age" (idiomatic with εἰς τὸν "forever")

ἀλλὰ strong adversative conjunction "but"

τὸ definite article nominative singular neuter "the"

ὕδωρ noun nominative singular neuter "water"

ὃ relative pronoun accusative singular neuter "which"

ἐγὼ pronoun nominative singular masculine "I"

δώσω verb future active indicative 1st singular from δίδωμι (I give) "I will give"

αὐτῷ pronoun dative singular masculine "to him"

γενήσεται verb future middle deponent indicative 3rd singular from γίνομαι (I become) "it will become"

ἐν dative preposition "in"

αὐτῷ pronoun dative singular masculine "to him"

πηγὴ noun nominative singular feminine "[a] spring"

ὕδατος noun genitive singular neuter "of water"

ἁλλομένου present middle participle genitive singular neuter from ἄλλομαι (I leap/I well up) "welling up"

εἰς accusative preposition "in/into"

ζωὴν noun accusative singular feminine "life"

αἰώνιον adjective accusative singular feminine "eternal"