John 6:58

οὗτός ἐστιν ὁ ἄρτος ὁ ἐξ οὐρανοῦ καταβάς, οὐ καθὼς ἔφαγον οἱ πατέρες καὶ ἀπέθανον· ὁ τρώγων τοῦτον τὸν ἄρτον ζήσει εἰς τὸν αἰῶνα.

Rough Word-by-word:
This is the bread the out of heaven having come down, not also as they ate the fathers and they died away. The one eating this the bread he will live into the age.

Smooth Translation:
This is the bread that has come down from heaven, not as the fathers ate and died away. The one eating this bread will live forever.

οὗτός demonstrative pronoun nominative singular masculine "this"

ἐστιν verb present indicative 3rd singular from εἰμί (I am) "[he] it is"

ὁ definite article nominative singular masculine "the"

ἄρτος noun nominative singular masculine "bread"

ὁ definite article nominative singular masculine "the"

ἐξ genitive preposition "from, out of"

οὐρανοῦ noun genitive singular masculine "heaven"

καταβάς aorist active participle nominative singular masculine from καταβαίνω (I come down) "having come down"

οὐ adverb of negation "not"

καθὼς compound conjunction and adverb "also as"

ἔφαγον verb aorist active indicative 3rd plural from ἐσθίω (I eat) "they ate"

οἱ definite article nominative plural masculine "the"

πατέρες noun nominative plural masculine "fathers"

καὶ conjunction "and"

ἀπέθανον verb aorist active indicative 3rd plural from ἀποθνήσκω (I die away) "they died away"

ὁ definite article nominative singular masculine "the"

τρώγων present active participle nominative singular masculine from τρώγω (I eat) "one eating"

τοῦτον demonstrative pronoun accusative singular masculine "this"

τὸν definite article accusative singular masculine "the"

ἄρτον noun accusative singular masculine "bread"

ζήσει verb future active indicative 3rd singular from ζάω (I live) "he will live"

εἰς accusative preposition "into, unto"

τὸν definite article accusative singular masculine "the"

αἰῶνα noun accusative singular masculine "age" (note: εἰς τὸν αἰῶνα is idiomatic - "forever")