Exegesis:

kai humeis ginesthe hetoimoi ‘you too must be ready,’ i.e. like the servants of vv. 37f and the master of the house of v. 39.

hetoimos ‘ready,’ ‘prepared.’

hoti hē hōra ou dokeite ho huios tou anthrōpou erchetai ‘for at the time you do not believe (him to come) the Son of man will come.’ hē hōra lit. ‘at which time,’ stands for tē hōra hē ‘at the time at which.’ For dokeō cf. on 8.18, for erchetai on v. 39.

Translation:

You also must be ready; for the Son of man is coming … The first clause may require a qualification, which may result in something like, ‘you also must be ready to receive/welcome the Son of man, for he will come….’ You also, or, ‘you likewise,’ ‘you just as he (or, that householder).’

At an hour you do not expect, or, adding a qualification again, ‘at a moment you do not expect him,’ ‘when you think, “He will not come now” .’ The verb in Toraja-Sa’dan is rendered by a reduplicated verbal derivation of the word for ‘perhaps/probably.’

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.