Exegesis:

ēn de tas hēmeras en tō hierō didaskōn ‘during the days he taught in the temple.’ The periphrastic imperfect ēn … didaskōn expresses duration. tas hēmeras is accusative of extent. For to hieron cf. on 2.27.

tas de nuktas ‘but during the nights,’ parallel to tas hēmeras and going with ēulizeto (see below).

exerchomenos ēulizeto lit. ‘going out he spent the night,’ i.e. ‘he went out and spent the night.’ exerchomenos refers to leaving Jerusalem, not only the temple.

aulizomai ‘to spend the night,’ ‘to lodge during the night.’

eis to oros to kaloumenon Elaiōn ‘on the mountain called (Mount) of Olives,’ cf. on 19.29. eis is used for en.

Translation:

At night, or, ‘every night.’

He went out and lodged, or, ‘he left (the city) and stayed,’ ‘he stayed/lodged outside (the city).’ The reference is to habitual action, habitual, that is to say, during the period in view.

Mount called Olivet, cf. on 19.29.

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.