A.T. Robertson Commentary 1 Thessalonians 5:6

"so then let us not sleep, as do the rest, but let us watch and be sober." — 1 Thessalonians 5:6 (ASV)

So then (αρα ουν). Two inferential particles, accordingly therefore, as in 2 Thessalonians 2:15 and only in Paul in N.T.

Let us not sleep (μη καθευδωμεν). Present active subjunctive (volitive), let us not go on sleeping.

Let us watch (γρηγορωμεν). Present active subj. (volitive) again, let us keep awake (late verb γρηγορεω from perfect εγρηγορα).

Be sober (νηφωμεν). Present active subjunctive (volitive). Old verb not to be drunk. In N.T. only in figurative sense, to be calm, sober-minded. Also in verse 8 with the metaphor of drunkenness in contrast.