Exegesis:

eperōtētheis de hupo tōn Pharisaiōn ‘when he was asked by the Pharisees,’ without indication of place or time and without connexion with the preceding narrative. For eperōtaō cf. on 2.46; for Pharisaios on 5.17.

pote erchetai hē basileia tou theou ‘when the kingdom of God would come.’ erchetai is used with future meaning. For hē basileia tou theou cf. on 4.43. The coming of the kingdom refers to the moment when God will exercise his royal power in full.

apekrithē autois kai eipen ‘he answered them and said,’ i.e. ‘he answered them by saying,’ or ‘he said to them in reply.’

ouk erchetai hē basileia tou theou meta paratērēseōs lit. ‘the kingdom of God will not come with observation.’

paratērēsis ‘observation’ (cf. paratereō 6.7; 14.1). meta paratērēseōs may mean either ‘in such a way as to be seen,’ or ‘in such a way as to be predictable by signs,’ preferably the latter.

(V. 21) oude erousin, Idou hōde; ē, Ekei ‘nor will people say, look here, or there,’ i.e., neither will the kingdom come in such a way that people can say, ‘look here, or there.’

idou gar hē basileia tou theou entos humōn estin ‘for behold, the kingdom of God is among you.’ idou contrasts emphatically with the preceding idou and introduces the clause which explains why the preceding delimitations of the coming of the kingdom are to be rejected. The meaning of entos humōn is much discussed, cf. commentaries, esp. Creed. The following renderings are possible: (1) ‘within you,’ i.e. ‘within your heart,’ taking basileia tou theou in a non-eschatological sense; (2) ‘among you,’ i.e. ‘in your midst,’ either now or in the future; (3) ‘within your reach.’ Of these (2) seems to be preferable.

Translation:

Being asked by the Pharisees, or, ‘once the Ph. asked him/Jesus.’

When the kingdom of God was coming, or, ‘when the time would come that God reigns.’

The kingdom of God is not coming with signs to be observed. The prepositional phrase has also been rendered by, ‘so that one/you can calculate it, or, divine it, or, see it beforehand’ (cf. Nieuwe Vertaling, Balinese, Sranan Tongo), ‘with signs (lit. things-that-may-be-seen)’ (one West Nyanja version). Further adjustments may lead to, ‘you/people cannot tell by observing signs when the kingdom of God will come’ (cf. New English Bible), ‘there are no signs that can tell you when God is going to rule,’ ‘no sign will be seen to appear when God begins to give orders’ (Tzeltal), ‘when the power of God comes there will not be a visible sign’ (Kekchi).

(V. 21) Nor will they say, or, ‘and no one will say’ (cf. Good News Translation).

‘Lo, here it is!’ or ‘There!’. An equivalent of “lo” is often better omitted, since the next words sufficiently express the demonstrative force of Gr. idou; cf. on “behold” in 1.20.

For behold, or, “for in fact” (New English Bible); or more strongly contrastive, ‘No!’

The kingdom of God is in the midst of you, or, ‘already God is ruling among you, or, giving orders in your midst’ (a San Miguel El Grande Mixtec dialect, Tzeltal), cf. interpretation (2) in Exegesis. A term covering both ‘within’ and ‘amongst’ cf. interpretation (1) and (2), is recorded for Shona, East Nyanja, Yao, Lomwe, Marathi.

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.