“Otherwise,
He may find you
Asleep,
When he comes
Suddenly.”
μὴ ἐλθὼν ἐξαίφνης εὕρῃ ὑμᾶς καθεύδοντας.
This saying is unique to Mark. Jesus warned that the land owner might find them asleep (εὕρῃ ὑμᾶς καθεύδοντας), if he returned or came back suddenly (μὴ ἐλθὼν ἐξαίφνης). You had to be vigilant all the time, including night time.