96 The second or third watch of the night would be between 9 p.m. and 3 a.m. on a Roman schedule and 10 p.m. to 6 a.m. on a Jewish schedule. Luke uses the four-watch schedule of the Romans in Acts 12:4, so that is more probable here. Regardless of the precise times of the watches, however, it is clear that the late-night watches when a person is least alert are in view here.
97 Grk “finds (them) thus”; but this has been clarified in the translation by referring to the status (“alert”) mentioned in v. 37.
98 Grk “blessed are they”; the referent (the watchful slaves, v. 37) has been specified in the translation for clarity.

In other versions

If he comes in the second watch, or in the third, and finds them awake, blessed are those servants!

It will be good for those servants whose master finds them ready, even if he comes in the middle of the night or toward daybreak.

If he comes in the middle of the night, or even near dawn, and finds them alert, blessed are those servants.

He may come in the middle of the night or just before dawn. But whenever he comes, he will reward the servants who are ready.

Even if he should come back in the second or in the third watch of the night and find them like this, blessed are they!

And if he shall come in the second watch, or come in the third watch, and find them so, blessed are those servants.

Public Domain