Exegesis:

Ierousalēm Ierousalēm ‘Jerusalem, Jerusalem,’ vocative; the repetition lends emphasis, cf. 10.41.

hē apokteinousa tous prophētas ‘you that kill the prophets,’ continuation of the vocative. The present tense denotes a habitual situation, cf. Plummer.

kai lithobolousa tous apestalmenous pros autēn ‘and stone those that have been sent to her,’ also dependent on the article hē before apokteinousa and continuation of the vocative. tous apestalmenous is best understood as referring to the same people as tous prophētas. pros autēn ‘to her,’ refers to Jerusalem in the third person though the clause addresses it in the second person; this is a Semitism. For apostellō cf. on 1.19.

lithoboleō lit. ‘to throw stones,’ hence ‘to kill by throwing stones,’ ‘to pelt to death with stones.’

posakis ēthelēsa episunaxai ta tekna sou ‘how often have I longed to gather your children.’ ta tekna sou does not refer to the inhabitants of Jerusalem only but implicitly to all that belong to the people of God.

posakis ‘how often,’ ‘how many times.’

episunagō (also 17.37) ‘to gather,’ synonymous with sunagō, cf. on 3.17.

hon tropon ornis tēn heautēs nossian hupo tas pterugas ‘just as a hen (gathers) her brood under her wings,’ with episunagei understood (cf. the parallel Mt. 23.37). hon tropon lit. ‘in the (same) way as,’ hence ‘just as.’

ornis, generally, ‘bird,’ here ‘hen,’ ‘cock,’ as a symbol of protecting care.

nossia ‘brood’ (cf. nossous in 2.24), here ‘chickens.’

kai ouk ēthelēsate ‘and you were not willing,’ ‘you would not have it.’

Translation:

O Jerusalem, Jerusalem, the city standing for its inhabitants, which may lead to, ‘O you, people of Jerusalem.’ The subsequent phrase (killing … sent to you), usually rendered as a relative clause, ‘you that (use to) kill…,’ may also be rendered as a sentence, e.g. ‘when(ever) prophets are sent (or, God sends prophets) to you, you kill and stone them.’

I would have gathered, or, ‘I have wanted/longed to gather.’ To gather … together, preferably, “to gather … around (or, to) me” (An American Translation, The Four Gospels – a New Translation).

Your children, or, ‘your people,’ ‘your inhabitants’; or simply ‘you,’ if the city’s people have been mentioned already.

Gathers … under her wings, or, ‘shelters … under her wings,’ ‘habitually covers its nest with its wings’ (one West Nyanja version). Some languages can render the phrase by a specific verb, e.g. Thai (lit. ‘to cover,’ said also of a hen that sits on its eggs), similarly Balinese.

You would not, or filling out the ellipsis, ‘you would not let me do so,’ ‘you did not want to be gathered (thus).’

Quoted with permission from Reiling, J. and Swellengrebel, J.L. A Handbook on the Gospel of Luke. (UBS Handbook Series). New York: UBS, 1971. For this and other handbooks for translators see here . Make sure to also consult the Handbook on the Gospel of Mark for parallel or similar verses.