You yourselves know well that the Day of the Lord will come just as a thief comes in the night.
For yourselves know perfectly that the day of the Lord so cometh as a thief in the night.
For you yourselves know perfectly well that the day of the [return of the] Lord will come [as unexpectedly and suddenly] as a thief in the night.
You know very well that the day of the Lord is going to come like a thief in the night.
For you yourselves thoroughly understand that the day of the Lord shall arrive much like a thief in the night.