Greek Study Matthew 5:13-16
v13 υμεις "you" – an emphatic εστε (ειμι) pres. "you are" - indicative statement, so not "be salt", but "you are salt".
της γης (η) "of the earth" – i.e. the human world. In what sense is this true? "Salt" is not a verbal noun so this is likely possessive, "you are the earth's salt".
μωρανθη (μωραινω) aor. pas. subj. "loses its saltiness" – an idiom meaning, becomes foolish = tasteless =saltless likely meaning “low grade" or “polluted/diluted”.
αλισθησεται (αλιζω) fut. "can it be made salty again" - The subject is της γης, "the earth", "how will the earth be made salty", but more likely το αλας, "the salt".
βληθεν (βαλλω) aor. part. "to be thrown" - "good for nothing, but to be cast out and trodden under foot".
καταπατεισθαι (καταπατεω) aor. pas. inf. "trampled" the infinitive here expresses the result of the saltless salt having no useful purpose, but it more properly forms an infinitival phrase, object of the verb ισχυει, "useful", standing in apposition to "for nothing".
v14 εστε (ειμι) "you are" indicative, "you are the light" addressing the disciples, Jesus is the light of the world (cf. Isaiah 42:6) and disciples are light in him.
του κοσμου (ος) "[the light] of the world" "you are the world's light".
κειμενη (κειμαι) pres. part. "[on a hill] / built [on a hill]" "a city which is lying on a hill."
κρυβηναι (κρυπτω) aor. pas. inf. "[cannot] be hidden" - infinitive is complementary.
v15 ουδε "neither" - links the clauses concerning the city and the lamp. Together they representing parallel impossibilities; “neither does someone light their house by removing all the bulbs. The bulbs are left in place so everyone can see."
καιουσιν (καιω) pres. "light" burn. Unlike απτω, "touch/light" this word emphasizes the action of keeping the lamp burning.
τον μοδιον (ος) "a bowl" – actually a 9 liter basket used for measuring grain.
v16 λαμψατω (λαμπω) aor. imp. "let [your light] shine" imperative, "shine your light".
εμπροσθεν + gen. "before" in front of - spacial. As the city and the lamp is visible to all so the light which radiates from the disciple should shine for all to see.
τα καλα εργα "good works" – a phrase common in the NT, occurring 30 times, but defined by the context. The "good works" here are explained in ethical terms: "living according to the values of the kingdom and manifesting the righteousness of the Torah/Law. But there is also a "mission perspective" for the light in the revelation of a particular kind of righteousness". This missionary function is not fulfilled by the application of the ethical demands of v21 on - this "good work" is the revelation of the saving activity of God in Christ. This is the work of the new Israel realized by making the gospel known
δοξασωσιν (δοξαζω) aor. subj. "praise" – worthy. "The works of disciples glorify GOd not the doers.